Use and method and processing arrangement therefor

Abstract

According to various embodiments, a chemical compound of boron with carbon is used as a target material for forming a layer (220) by means of a plasma to which the target material is exposed.

Description

[0001] Use, method and processing arrangement for this purpose

[0002] Various embodiments relate to a use, method and processing arrangement for this purpose.

[0003] In general, a substrate can be treated (processed) in a vacuum, for example by coating, so that its chemical and / or physical properties can be modified. Various coating processes can be used to coat a substrate, of which sputtering (also known as sputter deposition) is an established example of physical vapor deposition (PVD).

[0004] Sputtering involves ionizing a plasma-forming gas using a cathode (also known as a magnetron cathode). The resulting plasma can then be used to atomize the material to be deposited (target material). This atomized target material can subsequently be directed onto a substrate, where it can be deposited and form a layer. Sputtering can be used, for example, to deposit one or more layers onto a substrate.

[0005] However, for some materials, hurdles still exist that make it difficult to meet high requirements for the vapor deposition process and the resulting layer. These requirements include, among others, industrial scalability and the layer properties. Industrial scalability, in particular, poses challenges, as laboratory concepts cannot always be easily scaled up without compromising on requirements and / or cost-efficiency.

[0006] This applies particularly to electrically insulating materials, such as those containing silicate and / or boron, which are key components in semiconductor devices, e.g., in photovoltaics, and therefore have high economic value. Among other things, doped glass is used as a dopant donor, which is thermally excited to transfer the dopant (e.g., boron) to an adjacent semiconductor (also referred to as semiconductor material) or a chemical compound, preferably an oxide, of the semiconductor in which it is incorporated, for example, to produce an emitter or a passivating contact in a solar cell. This applies analogously to other coating materials that are difficult to deposit using PVD due to their properties (e.g., low electrical conductivity).By analogy, a semiconducting target material makes atomization using a plasma more difficult, since the electrical resistance of the target material is highly temperature-dependent, which complicates stable power control of the atomization process. Furthermore, not every chemical composition is industrially available as a target material, for example, due to manufacturing hurdles or high production costs. For instance, some materials and material combinations required to form a desired layer composition are not available as targets.

[0007] Several embodiments presented herein increase the applicability of PVD, including to materials (e.g., those containing a dopant) with low electrical conductivity. It has been demonstrated in various embodiments that the PVD target material is converted into a gaseous phase in which the components of the target material exist in atomic or ionized form and are therefore easier to separate. This is exploited in various embodiments to improve PVD. For example, a target material is provided that contains a chemical compound of the dopant with another chemical element (also called a sacrificial element). The gas phase of the coating material is exposed to a reaction gas (e.g., oxygen), which chemically reacts with the sacrificial element to form a volatile reaction product.

[0008] Several embodiments provided herein offer one or more target materials that facilitate atomization by means of a (e.g., pulsed or time-invariant) direct current. For this purpose, the target material can exhibit sufficiently high electrical conductivity (or at least a positive resistance-temperature coefficient, so that it is not semiconductor-like), which facilitates one or more of the following: atomization of the target material by means of a plasma, the provision of a stable coating process, and / or the elimination of plasma excitation by RF.In contrast to complex technical measures that, for example, allow sequential sputtering but require special modifications to the magnetron, the aspects provided herein facilitate the use of an established reactive sputtering process (for example, in an existing plant), for example, by exploiting an interaction of the chemical composition of the gas atmosphere and the target material.

[0009] The following are various examples that relate to what is described herein and depicted in the figures.

[0010] Example 1 is a target material (e.g. providing a sputtering target) that is based on a first chemical element (e.g. boron) and a second chemical element (e.g. carbon), is composed of them, and / or has a chemical compound (e.g. a carbide of boron, e.g. boron carbide) made up of them or consists of them.

[0011] Example 2 is set up according to Example 1, wherein the first chemical element (also referred to as the main element) reacts with a reactive gas (e.g. containing or consisting of oxygen, e.g. molecular oxygen) to form a first reaction product (e.g. an oxide) and the second chemical element (also referred to as the minor element) reacts with the reactive gas to form a second reaction product (e.g. an oxide), wherein the second reaction product transitions into the gaseous phase at a temperature that is lower (e.g. by a temperature difference) than: a temperature at which the first reaction product transitions into the gaseous phase and / or a temperature of standard conditions (0°C); and / or a process temperature (e.g. during operation of the target material).

[0012] Example 3 is set up according to Example 1 or 2, wherein the temperature difference is greater than approximately 50 Kelvin, e.g., greater than approximately 100 Kelvin, e.g., greater than approximately 200 Kelvin, e.g., greater than approximately 500 Kelvin; and / or wherein the process temperature is greater than approximately 200 Kelvin (e.g., greater than approximately 500 Kelvin).

[0013] Example 4 is set up according to Example 2 or 3, wherein the target material and / or a layer formed by means of the target material (also referred to as a functional layer) are exposed to the process temperature. Example 5 is set up according to one of Examples 1 to 4, wherein a layer formed by means of the target and / or by PVD (e.g., functional layer) contains or consists of the first reaction product.

[0014] Example 6 is set up according to one of Examples 1 to 5, wherein the target material and / or a layer formed by means of the target material are solid under standard conditions.

[0015] Example 7 is set up according to one of Examples 1 to 6, wherein the first chemical element, as a pure substance, has an electrical conductivity of less than 10 -3 S / m (or at least 10 -2 S / m).

[0016] Example 8 is set up according to any one of Examples 1 to 7, wherein the target material has boron as the first chemical element and / or carbon as the second chemical element. Example 9 is set up according to any one of Examples 1 to 8, wherein the first reaction product has an oxide and / or a glass (e.g., oxide and / or doped).

[0017] Example 10 is configured according to one of the appended claims and / or is a use of a target material, preferably configured according to one of Examples 1 to 9, as a sputtering target and / or for forming a layer, by means of physical vapor deposition (PVD) and / or by means of a plasma to which the target material is exposed.

[0018] Example 11 is the use (e.g. according to Example 10) of a chemical compound of carbon and boron as a target material and / or of a target material which preferably comprises or consists of boron and carbon (e.g. a chemical compound thereof) for forming a layer (e.g. over, preferably on, a semiconductor or a chemical compound, preferably oxide, of the semiconductor) by means of a plasma to which the target material is exposed (e.g. by means of which the target material is atomized), wherein the target material is preferably configured according to one of Examples 1 to 9.

[0019] Example 12 (e.g., using) is set up according to Example 10 or 11, wherein furthermore, doping of a semiconductor (e.g., through a chemical compound, preferably oxide, of the semiconductor) is carried out by means of the layer.

[0020] Example 13 is a method (e.g., for a semiconductor dopant) comprising: forming a layer by means of PVD and / or a plasma to which a target material is exposed, the target material being configured according to one of Examples 1 to 9 and / or comprising or consisting of the dopant (e.g., boron) and carbon (e.g., a chemical compound thereof); transferring an additional target material comprising the semiconductor, preferably silicon, and the semiconductor dopant into a gas phase, which is used to form the layer; and preferably doping a semiconductor (e.g., adjacent to the layer) by means of the layer. The transfer of the additional target material into the gas phase (also referred to as gaseous material) can be carried out by means of the plasma, for example, such that the gas phases of the target material and the additional target material interpenetrate each other, or by means of a spatially separated plasma, e.g.,such that the gas phases of target material and additional target material are spatially separated from each other.

[0021] Example 14 (e.g. a method or use) is set up according to one of Examples 1 to 13, wherein the layer is formed over, preferably on, the semiconductor or a chemical compound, preferably oxide, of the semiconductor (e.g. in contact with it).

[0022] Example 15 (e.g. a method or use) is set up according to any of Examples 1 to 14, wherein the layer has a glass having boron and / or the semiconductor (e.g. borosilicate glass).

[0023] Example 16 (e.g. a method or use) is set up according to any of Examples 1 to 15, wherein the layer has an oxide containing boron and / or the semiconductor (or at least a component, e.g. the main element, of the semiconductor if it is a compound semiconductor).

[0024] Example 17 (e.g., a method or use) is set up according to any one of Examples 1 to 16, wherein the plasma is exposed to a DC voltage (e.g., pulsed or time-invariant) and / or wherein the DC voltage is applied to the target material, preferably by means of which plasma formation is stimulated. Example 18 (e.g., a method or use) is set up according to any one of Examples 1 to 17, wherein the plasma is exposed to a magnetic field. Example 19 (e.g., a method or use) is set up according to any one of Examples 1 to 18, wherein a reactive gas, e.g., (e.g., molecular) oxygen, is supplied to the plasma and / or wherein the plasma contains (e.g., excited, atomic, and / or ionized) oxygen.

[0025] Example 20 (e.g., a method or use) is set up according to one of Examples 1 to 19, wherein the doping of the semiconductor is carried out by heating the layer and / or exciting a migration of boron from the layer into the semiconductor.

[0026] Example 21 (e.g. a process or use) is set up according to any of Examples 1 to 20, wherein the layer contains or consists of boron.

[0027] Example 22 (e.g., a process or use) is set up according to any one of Examples 1 to 21, further wherein a reaction product is formed which comprises the carbon, preferably by a chemical reaction of the carbon with the reactive gas (e.g., oxygen) and / or wherein the reaction product is gaseous. Example 23 (e.g., a process or use) is set up according to any one of Examples 1 to 22, further wherein the target material and / or the layer further comprises silicon.

[0028] Example 24 (e.g. a method or use) is set up according to one of Examples 1 to 23, wherein the target material and / or layer further comprises aluminium (which, for example, improves thermal conductivity).

[0029] Example 25 (e.g. a method or use) is set up according to any of Examples 1 to 24, wherein the semiconductor comprises or consists of silicon.

[0030] Example 26 (e.g. a method or use) is set up according to one of Examples 1 to 25, wherein the first chemical element (e.g. boron) is a dopant of the semiconductor.

[0031] Example 27 (e.g. a process or use) is set up according to any of Examples 1 to 26, wherein the chemical compound of carbon and boron includes or consists of a boron carbide.

[0032] Example 28 (e.g., a method or use) is set up according to one of Examples 1 to 27, wherein the formation of the layer is further carried out by means of an additional target material which is atomized by means of a plasma and / or comprises the semiconductor (e.g., a carbide thereof) and / or the dopant (e.g., in the form of SiB), wherein preferably a first stream of gaseous material (also referred to as a vapor stream) is generated towards the layer by means of the target material, and preferably a second stream of gaseous material is generated towards the layer by means of the additional target material, which, for example, penetrate each other or are spatially separated from each other (e.g., having a distance between them). Interpenetrating vapor streams promote a homogeneous chemical composition of the layer.In this regard, it can be understood that, alternatively, a stack of sublayers (also called layers) can be formed as a layer, which differ from each other in their chemical composition (e.g. in their proportion of boron and / or the semiconductor).

[0033] Example 29 (e.g., a method or use) is set up according to one of Examples 1 to 28, wherein the semiconductor and the target material (or at least the layer) are identical in a material (e.g., silicon) which has these properties.

[0034] Example 30 (e.g., a method) is configured to control one or more than one actuator to form a layer by using the method and / or procedure according to any of Examples 1 to 29. Example 31 is a computer program that is configured (e.g., having code segments that, when executed by a processor, are configured to cause the processor to perform the method according to Example 30 (e.g., by means of a processor).

[0035] Example 32 is a computer-readable medium that stores instructions which, when executed by a processor, are set up to cause the processor to perform the procedure according to Example 30.

[0036] Example 33 is a control device comprising one or more processors configured to perform the procedure according to Example 30.

[0037] Example 34 is a processing arrangement comprising: a vacuum chamber, a sputtering device arranged in the vacuum chamber for forming a layer by means of a plasma to which a target material of the sputtering device is exposed, a substrate holder which is configured to hold a substrate which preferably comprises a semiconductor and / or on which the layer is preferably formed, in the vacuum chamber, wherein the target material is preferably configured according to one of Examples 1 to 29 and / or comprises or consists of boron and carbon (e.g. a chemical compound thereof).

[0038] Example 35 is set up according to any one of Examples 1 to 34, wherein the target material is atomized by means of the plasma; and / or wherein the PVD is configured to form a plasma to which the target material is exposed. Example 36 is set up according to any one of Examples 1 to 35, wherein a (e.g., sprayed) sputtering target is provided by means of the target material.

[0039] Example 37 is set up according to one of Examples 1 to 36, further comprising: applying an electrical voltage to the target material, wherein the electrical voltage is a (e.g. unpulsed or pulsed) DC voltage or AC voltage; atomizing the target material by means of the plasma, wherein the plasma is formed by means of the electrical voltage.

[0040] Example 38 is set up according to one of Examples 1 to 37, wherein the first chemical element is a dopant (also called a dopant) of a semiconductor material (e.g. silicon).

[0041] Example 39 is set up according to one of Examples 1 to 38, further comprising: atomizing the target material by means of a plasma, doping a semiconductor layer by means of the first chemical element; wherein the doping (e.g., introduction of the dopant) of the semiconductor layer preferably has a positive electrical polarity.

[0042] Example 40 is set up according to one of Examples 1 to 39, wherein the layer comprises amorphous silicon.

[0043] Example 41 is set up according to one of Examples 1 to 40, wherein the reactive gas is supplied to the plasma; and / or wherein the target material is exposed to the reactive gas.

[0044] Example 42 is set up according to one of Examples 1 to 41, wherein the target material has the second chemical element with a molar (or weight) fraction of more than 5% (e.g., 10%, 15%, 20%) and / or less than 50% (e.g., 40%, 30%). This favors PVD.

[0045] Example 43 is set up according to one of Examples 1 to 42, wherein the target material contains the second chemical element in a molar (or weight) ratio to the first chemical element of more than 5% (e.g., 10%, 15%, 20%) and / or less than 50% (e.g., 40%, 30%). This favors PVD.

[0046] Example 44 is set up according to any one of Examples 1 to 43, wherein the target material comprises or consists of a chemical compound of the second chemical element with the first chemical element. Example 45 is set up according to any one of Examples 1 to 44, wherein the target material is transferred into a first gaseous phase while an additional target material is transferred into a second gaseous phase, the layer preferably being formed based on the first gaseous phase and the second gaseous phase, e.g., based on a mixture of the first gaseous phase and the second gaseous phase.

[0047] Example 46 is set up according to Example 45, wherein the additional target material comprises a semiconductor material (e.g. silicon) and / or the first chemical element, e.g. a semiconductor material doped with the first chemical element.

[0048] Example 47 is set up according to one of Examples 1 to 46, wherein the target material and / or the additional target material has a positive resistance-temperature coefficient, or at least has an electrical (e.g. specific) resistance (e.g. resistance, e.g. resistivity) which increases or decreases with increasing temperature.

[0049] Example 48 is set up according to one of Examples 1 to 47, wherein the layer formation is carried out by means of a DC voltage which is applied to the target material (e.g. between the target material and the additional target material) and is optionally inverted periodically (once or more than once).

[0050] Example 49 is set up according to one of Examples 1 to 48, wherein the target material has a weight fraction of the chemical compound of boron and carbon (e.g. boron carbide) of more than 50%, e.g. 75%, e.g. 90%, e.g. 95%.

[0051] Example 50 is set up according to one of Examples 1 to 49, wherein the target material is injected (e.g. to a target) which is preferably exposed to the plasma.

[0052] Example 51 is set up according to one of Examples 1 to 50, wherein the second chemical element reacts chemically with a reactive gas to form a volatile reaction product, which is removed by means of a vacuum pump and / or is not incorporated into the layer.

[0053] Example 52 is set up according to one of Examples 1 to 51, wherein the plasma (e.g. ionized, excited, atomic and / or molecular) has a reactive gas (e.g. oxygen) (and / or is formed by means of which) and / or wherein the reactive gas (e.g. oxygen) is supplied to the plasma, wherein the reactive gas (e.g. the oxygen) preferably reacts chemically with the accessory element (e.g. carbon).

[0054] Example 53 is set up according to one of Examples 1 to 52, wherein a chemical reaction of the minor element (e.g. carbon) with the reactive gas (e.g. oxygen) is carried out to form a gaseous (e.g. molecular) reaction product (e.g. under standard conditions), wherein preferably the reaction product is separated from the plasma (or the coating process).

[0055] Example 54 is set up according to one of Examples 1 to 53, wherein a reactive gas, e.g., oxygen (e.g., as the reactive gas), is used to separate the accessory element (e.g., carbon) from the plasma (or the coating process) to which the target material is exposed and / or which is supplied to the plasma. Example 55 is set up according to one of Examples 1 to 54, wherein the plasma is reactive (e.g., by means of the reactive gas).

[0056] Example 56 is set up according to one of Examples 1 to 55, wherein the (oxide and / or doped) glass is used as a dopant donor, which is thermally excited to release a dopant (e.g. boron) from the glass to an adjacent semiconductor in which it is incorporated, for example to produce an emitter or a passivating contact in a solar cell.

[0057] Example 57 is set up according to one of Examples 1 to 56, wherein the layer has a stack of sublayers (also called layers) which differ from each other in their chemical composition (e.g. in their proportion of boron and / or the semiconductor).

[0058] Example 58 is set up according to one of Examples 1 to 57, wherein the layer is formed on a substrate and furthermore by means of an additional target material which is atomized by means of a plasma and / or contains the semiconductor (e.g., a carbide thereof), wherein the substrate is transported several times successively towards the target material and away from the additional target material during layer formation (e.g., performing a pendulum motion). This promotes the formation of a stack of sublayers (also called layers) which differ from one another in their chemical composition (e.g., in their proportion of boron and / or the semiconductor).

[0059] Example 59 is set up according to one of Examples 1 to 58, wherein a first stream of gaseous material (also referred to as the first vapor stream), generated by the target material, and a second stream of gaseous material (also referred to as the second vapor stream), generated by the additional target material, are spatially separated from each other (e.g., by a distance between them), wherein the substrate for forming the layer is transported several times successively from the first vapor stream into the second vapor stream, and subsequently from the second vapor stream into the first vapor stream (e.g., performing a pendulum motion). This favors the formation of the stack of sublayers (also referred to as layers) which differ from each other in their chemical composition (e.g., in their proportion of boron and / or the semiconductor).

[0060] Example 60 is set up according to one of Examples 1 to 59, wherein the formation of the layer takes place on the substrate which is placed in a substrate carrier by means of which the substrate is transported.

[0061] Example 61 is set up according to one of Examples 1 to 60, wherein, upon heating the layer and / or exciting the migration of the dopant from the layer into the semiconductor, a mixing of several layers of the layer occurs, which previously differ from each other in their chemical composition (e.g., in their proportion of boron and / or the semiconductor).

[0062] Example 61 is set up according to one of Examples 1 to 60, wherein the layer comprises the semiconductor material, e.g., an oxide thereof (e.g., silicon dioxide), and / or the boron; and / or wherein the semiconductor material comprises silicon. For example, the layer may comprise or consist of boron-doped silicon dioxide.

[0063] Example 62 is set up according to one of Examples 1 to 61, wherein the plasma is free of nitrogen or has a greater proportion of oxygen than nitrogen; and / or wherein the plasma has more than 50% oxygen (e.g. more than 75%, e.g. more than 90%).

[0064] Example 63 is set up according to one of Examples 1 to 62, wherein the layer has a larger ratio (e.g., based on a quantity, e.g., a proportion) of boron to the at least one minor element (e.g., carbon) than the target material. For example, the target material may have a quantity ratio (e.g.,

[0065] Example 64 is set up according to one of Examples 1 to 63, wherein the layer has a smaller proportion of the at least one minor element (e.g., carbon) (e.g., relative to the proportion of boron) than the target material and / or has a smaller proportion of carbon to boron than 0.25 (e.g., than 0.2, e.g., than 0.1, e.g., than 0.01).

[0066] Example 65 is set up according to one of Examples 1 to 64, wherein more than 50% (e.g. more than 75%, e.g. more than 90%) of the at least one minor element react chemically to form the gaseous reaction product.

[0067] Example 66 is set up according to one of Examples 1 to 65, wherein the layer contains less (e.g. a smaller proportion) than 10% (e.g. weight percent) boron, e.g. less than 5% (e.g. weight percent) boron and / or less (e.g. a smaller proportion) boron as semiconductor material.

[0068] Example 67 is set up according to one of Examples 1 to 66, wherein the layer contains less (e.g. a smaller proportion) than 10% (e.g. weight percent) of the minor element, e.g. less than 5% (e.g. weight percent) of the minor element, e.g. less than 1% (e.g. weight percent) of the minor element, e.g. less than 0.1% (e.g. weight percent) of the minor element, e.g. less than 0.01% (e.g. weight percent) of the minor element, and / or contains less (e.g. a smaller proportion) of the minor element than boron.

[0069] Example 68 is set up according to one of Examples 1 to 67, wherein the layer contains more of the boron (e.g. a larger proportion thereof) than of the at least one minor element (e.g. based on weight or mole fraction).

[0070] Example 69 is set up according to one of Examples 1 to 68, wherein the semiconductor material and the at least one minor element are identical in their valence (also called valence or number of valence electrons) and / or are from the same group (e.g. main group) of the periodic table.

[0071] Example 70 is set up according to one of Examples 1 to 69, wherein the layer is formed on a ceramic surface and / or on a wafer.

[0072] Example 71 (preferably set up according to one of Examples 1 to 70) is the use of a plasma formed by means of a reactive gas to stimulate a chemical reaction of the reactive gas with a minor element contained in the target material, wherein the target material further comprises a dopant (e.g. boron).

[0073] Example 72 (preferably set up according to any one of Examples 1 to 71) is the use of a plasma to reduce a ratio between the minor element and boron in a material stream emitted from a target material exposed to the plasma; wherein a layer is formed by means of a result (e.g. a chemical composition of the material stream as a result) of the reduction, wherein the plasma is preferably formed by means of a reactive gas which is set up to react with the minor element to give a gaseous reaction product under standard conditions and / or vacuum.

[0074] Example 73 is set up according to one of Examples 1 to 72, wherein the plasma is free of nitrogen or at least contains less nitrogen than oxygen (e.g., in terms of proportion, e.g., at%). This inhibits the formation of a nitride, e.g., carbon, which is non-volatile.

[0075] Example 74 is set up according to one of Examples 1 to 73, wherein the layer is free of nitrogen or at least contains less nitrogen than oxygen (e.g., based on the proportion, e.g., at%); and / or wherein the layer is free of the minor element (e.g., carbon) or at least contains less of the minor element (e.g., carbon) than oxygen (e.g., based on the proportion, e.g., at%). Example 75 is set up according to one of Examples 1 to 74, wherein the layer contains less of the minor element (e.g., carbon) than nitrogen (e.g., based on the proportion, e.g., at%).

[0076] Example 76 is set up according to one of Examples 1 to 75, wherein the layer contains less of the dopant (e.g. boron) than oxygen (e.g. based on the proportion, e.g. at%); and / or wherein the layer contains less of the dopant (e.g. boron) than of the semiconductor (e.g. silicon) (e.g. based on the proportion, e.g. at%).

[0077] Example 77 is set up according to one of Examples 1 to 76, wherein the layer contains more oxygen than that of the semiconductor (e.g. in a ratio of 2 or more based on at%), preferably silicon.

[0078] Example 78 is set up according to one of Examples 1 to 77, wherein the plasma is exposed to a pressure in a range from approximately 0.1 (e.g. 1) pibar to approximately 50 (e.g. 10) pibar (microbar); and / or wherein the plasma contains argon or at least argon (e.g. as a working gas) is supplied to the plasma.

[0079] Example 79 is set up according to one of Examples 1 to 78, wherein the target material contains more of the dopant (e.g., boron) than of the minor element (e.g., carbon) (e.g., based on the proportion, e.g., at%). Example 80 is set up according to one of Examples 1 to 79, wherein the quantity (e.g., more than, less than, etc.) is based on a quantity of substance.

[0080] According to various embodiments, co-PVD (e.g., co-sputtering) does not necessarily have to be carried out using interpenetrating vapor streams. The substrate, which is placed, for example, in a substrate carrier, can be coated alternately with the dopant (e.g., boron from the boron carbide as the target material) and with boron-doped silicon (e.g., from the additional target material), for example, according to a desired molar composition. This can promote the formation of a stack of several layers (also called stacking) without the vapor streams necessarily having to interpenetrate each other. The resulting stack can still lead to the desired diffusion in the subsequent temperature process. The stack can, for example, have several stacked pairs of layers, each pair having a first layer of SiOx (or Si:BOx) and a second layer of BOx.

[0081] This document refers, by way of example, to a chemical compound of boron and carbon as a target material. It should be understood that the description provided is not limited to this exemplary chemical composition of the target material and can apply by analogy to any other target material that is set up and / or used according to any one of Examples 1 to 79. In particular, this document refers to boron as an exemplary dopant of silicon as an exemplary semiconductor material. It should be understood that the description provided is not limited to the context of a semiconductor material, e.g., the doping of the semiconductor material, and can apply by analogy to any other chemical element in a target material that is set up and / or used according to any one of Examples 1 to 79.

[0082] They show

[0083] Figure 1A shows a use of the target material in a process according to different embodiments in a schematic flowchart;

[0084] Figure 1B illustrates a coating process using PVD (e.g., sputtering) according to various embodiments in a schematic process diagram; Figure 2A illustrates a coating process using PVD according to various embodiments in a schematic process diagram;

[0085] Figure 2B shows a coated substrate as a result of a process and / or use according to various embodiments in a schematic perspective view;

[0086] Figure 3 shows a coating process using PVD according to various embodiments in a schematic process diagram; and

[0087] Figures 4A and 4B each show a processing arrangement according to different embodiments in a schematic cross-sectional view or side view.

[0088] The following detailed description refers to the accompanying drawings, which form part thereof and illustrate specific embodiments in which the invention can be implemented. In this context, directional terminology such as "top," "bottom," "front," "back," "anterior," "rear," etc., is used with reference to the orientation of the described figure(s). Since components of embodiments can be positioned in a number of different orientations, the directional terminology serves only for illustration and is in no way limiting. It is understood that other embodiments may be used and structural or logical modifications may be made without deviating from the scope of protection of the present invention.It is understood that the features of the various exemplary embodiments described herein can be combined with one another, unless specifically stated otherwise. The following detailed description is therefore not to be interpreted in a limiting sense, and the scope of protection of the present invention is defined by the appended claims.

[0089] Within the scope of this description, the terms "connected," "connected," and "coupled" are used to describe both direct and indirect connections (e.g., resistive and / or electrically conductive, such as an electrically conductive connection), direct or indirect connections, and direct or indirect couplings. In the figures, identical or similar elements are designated with identical reference numerals where appropriate. According to various embodiments, the term "coupled" or "coupling" can be understood as a connection and / or interaction (e.g., mechanical, hydrostatic, thermal, and / or electrical), e.g., direct or indirect. Several elements can, for example, be coupled to one another along an interaction chain, along which the interaction can be exchanged, e.g., a fluid (then also referred to as fluid-conducting coupled).For example, two coupled elements can interact with each other, e.g., a mechanical, hydrostatic, thermal, and / or electrical interaction. A coupling of several vacuum components (e.g., valves, pumps, chambers, etc.) can involve fluid coupling.

[0090] According to various embodiments, "coupled" can be understood in the sense of a mechanical (e.g., physical) coupling, for example, by means of direct physical contact. A coupling can be designed to transmit a mechanical interaction (e.g., force, torque, etc.). The actual state of an entity (e.g., a device, a system, or a process) can be understood as the actual or sensorily detectable state of the entity. According to various embodiments, a bearing device can be designed to support (e.g., guided positioning and / or holding) one or more components. For example, the bearing device can have one or more bearings per component for supporting (e.g., guided positioning and / or holding) the component.Each bearing of the loading device can be configured to provide the component with one or more degrees of freedom (for example, translational or rotational degrees of freedom) according to which the component can be moved. Examples of bearings include: radial bearings, thrust bearings, radial-axial bearings, and linear bearings (also known as linear guides). Each linear bearing can, for example, provide the component with exactly one translational degree of freedom.

[0091] According to various embodiments, the vacuum chamber can be provided by means of a chamber housing in which one or more chambers are provided. The chamber housing can, for example, be coupled to a pump arrangement, e.g., a vacuum pump arrangement (e.g., gas-conducting), to provide a negative pressure or a vacuum (vacuum chamber housing) and be designed to be stable enough to withstand the effects of atmospheric pressure in the evacuated state. The pump arrangement (comprising at least one vacuum pump, e.g., a high-vacuum pump, e.g., a turbomolecular pump) can enable the removal of some of the gas from the interior of the processing chamber, e.g., from the processing space. Accordingly, one or more vacuum chambers can be provided in a chamber housing. In other words, the chamber housing can be configured as a vacuum chamber housing.A coating chamber can be set up as a vacuum chamber.

[0092] The term "vacuum pressure" here refers to a negative pressure in the vacuum range (i.e., a pressure of less than 0.3 bar), e.g., a pressure in a range of approximately 10 mbar to approximately 1 mbar (in other words, rough vacuum) can be provided, or less, e.g., a pressure in a range of approximately 1 mbar to approximately 10 3 mbar (in other words, fine vacuum) or less, e.g., a pressure in a range of approximately 10‰. 3 mbar to approximately 10 7 mbar (in other words, high vacuum) or less, e.g., a pressure of less than high vacuum, e.g., less than approximately 10 7 mbar.

[0093] A drive device can be understood here as a converter designed to transform electrical energy into mechanical energy. A drive device can, for example, comprise an electric motor (e.g., with electrical coils). A drive device can, for example, comprise a compressor and a piston coupled to it. A drive device can, for example, comprise one or more piezoelectric elements. For example, the drive device can be configured to output the mechanical energy by means of a torque or a rotary motion.

[0094] This document refers to various material specifications, such as their electrical conductivity and / or phase transition temperature. These specifications are based on standard conditions, i.e., 101,325 Pascals, and, if no temperature is specified, 0°C. A temperature specification may refer to the material at temperatures below 101,325 Pascals.

[0095] In various embodiments, the fabrication of contact layers in crystalline photovoltaics, for example a doped a-Si layer (amorphous silicon layer), is achieved using a sputtering process. A dopant used in this process can be, for example, boron. The term "sputtering" refers to the atomization of a material (also called coating material or target material) using a plasma. The atomized components of the target material are thus separated from one another and can, for example, be deposited elsewhere to form a layer. Sputtering can be carried out using a coating device (then also called a sputtering device), which may include a magnetic system (then also called a magnetron).The target material can be provided by means of a so-called sputtering target, which can be, for example, tubular (then also referred to as a tube target) or plate-shaped (then also referred to as a plate target). To generate the plasma, a voltage can be applied to the sputtering target (also referred to simply as the target), so that the sputtering target operates as the cathode. Even if the voltage is alternating current, the term cathode is retained.

[0096] The reactive gas can be a gaseous material that reacts with the target material (and / or with the atomized target material) and / or can be incorporated into the deposited layer via a chemical reaction (e.g., oxygen, nitrogen, nitrogen oxides, carbon oxides, and / or ozone). For example, if a target material is used that can form a nitride (e.g., AlNy), or if a nitride of the target material is to be deposited, the reactive gas can contain or be composed of nitrogen. If, for example, a target material is used that can form an oxide (e.g., AlOx), or if an oxide of the target material is to be deposited, the reactive gas can contain or be composed of oxygen. The reactive gas can, for example, be a gas mixture (reactive gas mixture) of several gases that react with the target material and / or the deposited layer (e.g., oxygen and nitrogen).when an oxynitride (e.g., AlOxNy) is to be deposited. The reactive gas mixture can, for example, consist predominantly (i.e., more than 50%) of oxygen, e.g., for the deposition of an oxide or oxynitride. According to various embodiments, the reactive gas can contain at least one of the following: oxygen, nitrogen, hydrogen sulfide, methane, gaseous hydrocarbons, fluorine, chlorine, or another gaseous material. According to various embodiments, the working gas can contain a gaseous material that is unreactive, in other words, that participates in only a few chemical reactions. A working gas can, for example, be defined by and adapted to the target material used. For example, a working gas can contain a gas or a gas mixture that does not react with the magnetron cathode or the target material to form a solid. The working gas can, for example, be a noble gas (e.g.,The working gas may consist of helium, neon, argon, krypton, xenon, radon) or several noble gases. The plasma, which essentially causes the sputtering of the magnetron cathode (also called sputtering cathode) or the target material, can be formed from the working gas.

[0097] The reactive gas may exhibit higher chemical reactivity than the working gas, for example, with respect to the coating material. In other words, the atomized target material may react faster with the reactive gas (i.e., form more reaction product per unit time) than with the working gas (e.g., if it reacts chemically with the working gas at all). The reactive gas and the working gas can be supplied together or separately as a process gas (e.g., as a gas mixture), for example, via the gas supply.

[0098] The target material can be sputtered (atomized) using the working gas, and a chemical compound (in other words, the reaction product) can be formed using a supplied reactive gas. This compound can be, for example, a metal compound or a metalloid compound, which can then be deposited onto a substrate. For instance, the chemical compound can be a metal oxide (e.g., AlOx) or metalloid oxide with oxygen as the reactive gas, a metal nitride (e.g., AlNy) or metalloid nitride with nitrogen as the reactive gas, a metal oxynitride (e.g., AlOxNy) or metalloid oxynitride with both oxygen and nitrogen as reactive gases, or another metal compound or metalloid compound with a different reactive gas (e.g., a metal carbide or metalloid carbide using a carbon-containing reactive gas). In other words, the layer material to be deposited (in other words, the reaction product) can be a metal and / or a metalloid.

[0099] A chemical element can be understood as a substance (also called a pure substance) that cannot be broken down into other substances by chemical methods. The smallest possible quantity of a chemical element is the atom. All atoms of a chemical element have the same number of protons in their nucleus (which is equal to the atomic number). Therefore, atoms of the same chemical element have the same electron shell structure and consequently behave chemically in the same way.

[0100] The term "coating material" here generally refers to a material by means of which a coating process can be carried out in which one or more layers are formed (also referred to as coating). The coating material can, for example, have the same chemical composition as the layer (then also referred to as the coating material) or react chemically with the coating material. Alternatively or additionally, the coating material can be provided in the form of a target (then also referred to as the target material).

[0101] The term "target material" refers to the material to be converted into a gaseous state (e.g., coating material and / or the target material), which is, for example, the layer-forming material or chemically reacts to form the layer-forming material. The coating material is incorporated into the layer formed on the substrate. For example, the layer can consist of the layer-forming material itself. For the sake of clarity, reference is made here, among other things, to an electrically insulating coating material, whereby the descriptions for this can apply analogously to a target material that is electrically conductive and / or chemically reacts to form an electrically insulating layer-forming material. More generally, the descriptions for the coating material can apply analogously to the target material and vice versa.

[0102] The term coating device here refers to a device configured to carry out a film-forming process (also referred to as a coating process) and may, for example, include a so-called material source. According to various embodiments, the coating device may be configured to coat at least one substrate (i.e., one substrate or several substrates), which is transported, for example, through a coating area. For instance, the coating device may be configured to provide a gaseous coating material (material vapor) and / or a liquid coating material, which can be deposited, for example, onto the at least one substrate to form a layer.Examples of components of a coating device include: a sputtering target as a material source, a plasma source, a crucible as a material source for thermal evaporation of the coating material (e.g., using a laser, electric arc, electron beam, and / or conductively supplied heat), a precursor source as a material source, and / or a liquid-phase atomizer as a material source. A sputtering device can be configured to atomize the sputtering target using a plasma. Regarding the film-forming process, vapor deposition is used as an example of a coating process, e.g., physical vapor deposition (PVD), which is distinct from chemical vapor deposition (CVD).Unlike CVD, PVD involves first converting a solid coating material (provided as the target) into the gas phase (also known as the gaseous phase or vapor) and then forming a layer using this gas phase. In PVD, the gas phase of the coating material can optionally react chemically with a reactive gas to form a chemical compound (also called the reaction product), which is then incorporated into the layer or forms the layer itself. Thus, in the chemical reaction of PVD, two or more materials are combined to form the chemical compound.In chemical vapor deposition (CVD), a gaseous starting compound (also called precursor or reactant) is split into at least two reaction products. At least one of these first reaction products is incorporated into the coating layer as a coating material, and optionally, a second reaction product is removed from the coating process as an excess (e.g., by means of a pump). Optionally, CVD can be performed using a plasma in which the precursor splits.

[0103] Electrically insulating can be understood here as having an electrical conductivity of less than approximately -10 -1 exhibiting S / m (Siemens per meter), e.g. less than approximately 10 -3 S / m, e.g. less than approximately 10 -4 S / m, e.g. less than approximately 10 -5 S / m, e.g. less than approximately 10 -6S / m. Electrical conductivity can be, for example, the real (i.e., ohmic) part of the generally complex electrical conductivity and / or at room temperature (e.g., under standard conditions).

[0104] The resistance-temperature coefficient denotes the temperature coefficient of the electrical resistance R (e.g., resistivity) of an object and can be expressed, for example, according to the relation R(T)= R(T0) ■ (1 + g-(T- TO)), where R(T) denotes the electrical resistance of the object at temperature T and R(T0) denotes the electrical resistance of the object at temperature TO (e.g., as a reference).

[0105] This refers to various details regarding the quantity of one or more than one material, for example

[0106] - in relation to the amount of a reference material (also referred to as quantity ratio, e.g. specified as doping strength (e.g. as atom number ratio) or as mass ratio;

[0107] - as a proportion, for example, of the total mass (then also referred to as mass fraction, e.g., expressed as wt%) of a reference, of the total volume (then also referred to as volume fraction, e.g., expressed as vol%) of the reference or of the amount of substance of the reference (then also referred to as mole fraction, e.g., expressed as at%), where the reference comprises the material, or

[0108] - as concentration (e.g., expressed as the number of atoms per volume, e.g., in at / cm³) 3 ).

[0109] The reference material can be, for example, the body (e.g., the sputtering target or a layer) containing the material, or a material mixture (e.g., of semiconductor material and dopant) containing the material. The material mixture can, for example, be a binary mixture. The reference material can, for example, be a different material than the material being measured, e.g., the semiconductor material.

[0110] Fig. 1A illustrates a method for using a target material, e.g., boron carbide as the target material, according to various embodiments 100a in a schematic flowchart, wherein the target material is preferably configured according to one of Example 1 to Example 12. An exemplary implementation of the target material has a dopant (e.g., boron) as the first chemical element and / or is provided as a sprayed sputtering target.

[0111] The process can include: in 101, the formation of a layer (also referred to as a functional layer) by means of physical vapor deposition using the target material (e.g., containing a dopant). An exemplary implementation of physical vapor deposition is carried out using a plasma by which the target material is atomized.

[0112] The process can optionally include: in 103, doping of a semiconductor material (e.g., a semiconductor layer) by means of the functional layer (then also referred to as the dopant donor layer), which, for example, borders the semiconductor material. The doping can involve migration of the dopant from the dopant donor layer into the semiconductor material, which is, for example, thermally excited.

[0113] An exemplary implementation of the target material can consist of or comprise a chemical compound of the dopant (as an exemplary first chemical element) and carbon (as an exemplary second chemical element). Alternatively or additionally, the target material can be provided in the form of a tubular target. The target can also be plate-shaped.

[0114] An exemplary implementation of the chemical compound as a target material is boron carbide. If the target material consists essentially of boron carbide, for example, the target can also be referred to as a boron carbide target.

[0115] In semiconductor technology, doping refers to the introduction of atoms of a dopant (also called dopant) into the base material of a semiconductor (also called semiconductor material). For example, a semiconductor layer may contain or be composed of the semiconductor material. The amount of dopant atoms introduced during this process is very small compared to the atoms of the base material (between 0.1 and 100 ppm, i.e., parts per million). The dopant atoms can, for example, create defects in the semiconductor material and optionally alter its electrical properties, i.e., the behavior of the electrons and thus its electrical conductivity. Even a small density of dopant atoms can cause a very large change in electrical conductivity.

[0116] When the electrical conductivity of a semiconductor material is changed, a distinction is made between p-doping (i.e., doping with positive polarity) and n-doping (i.e., doping with negative polarity). In p-doping, dopant atoms are introduced that act as electron acceptors. In n-doping, dopant atoms are introduced that act as electron donors.

[0117] To modify the electrical conductivity of a silicon or germanium semiconductor material (or more generally, a semiconductor material from group 4), a dopant from group 3, such as boron, indium, aluminum, or gallium, can be used for p-type doping. To modify the electrical conductivity of a silicon or germanium semiconductor material (or more generally, a semiconductor material from group 4), a dopant from group 5, such as phosphorus, arsenic, or antimony, can be used for n-type doping.

[0118] The semiconductor material to be doped (e.g., the semiconductor layer) can, however, also be a semiconductor material other than silicon or germanium, or be composed of such materials. For example, the semiconductor layer (e.g., on a wafer or other suitable substrate) or the semiconductor material to be doped can be made of or be made of semiconductor materials of various types, including a Group IV semiconductor (e.g., silicon or germanium), a Group I II-V semiconductor (e.g., gallium arsenide), or other semiconductor types, including, for example, Group I II semiconductors, Group V semiconductors, or polymers. In various embodiments, the semiconductor material or the semiconductor layer (e.g., a substrate) is made of (e.g., undoped) silicon. Alternatively, any other suitable semiconductor material can be used, e.g., for the semiconductor layer, such as a semiconductor compound material.Gallium phosphide (GaP), indium phosphide (InP), but also any suitable ternary semiconductor compound material, such as indium gallium arsenide (InGaAs), or quaternary semiconductor compound material.

[0119] More generally, semiconductor materials can have a valence that, in the case of elemental semiconductors (e.g., Group I or Group IV semiconductors), corresponds to the value of the semiconductor's main group, and in the case of compound semiconductors, corresponds to the average value of the main groups of the compound semiconductor's constituents. For example, Group 111-V compound semiconductors can have a valence of 4. The Group III-V semiconductor gallium arsenide (GaAs), for instance, can be positively doped with a dopant such as carbon and negatively doped with tellurium.

[0120] More generally speaking, the dopant can be from a main group whose value differs from the valence of the semiconductor material, i.e., is smaller or larger than it (e.g. by the value 1).

[0121] Doping can have the effect of increasing the concentration (also called doping concentration) of the atoms of the dopant (also called dopant atoms) in the semiconductor material (e.g., the semiconductor layer), e.g., to 1 dopant atom / 10 7 Semiconductor atoms (atoms of the semiconductor material) or more, e.g., 1 dopant atom / 10 6 Semiconductor atoms or more, e.g., 1 dopant atom / 10 5 Semiconductor atoms or more, e.g., 1 dopant atom / 10 4 Semiconductor atoms or more, e.g., 1 dopant atom / 10 3 Semiconductor atoms or more.

[0122] Optionally, the semiconductor layer can be amorphous. For example, the atoms of the semiconductor layer (i.e., the semiconductor atoms) can form an irregular pattern rather than ordered structures, and may only possess short-range order, but not long-range order.

[0123] Optionally, doping can involve activating the dopant introduced into the semiconductor material, e.g., thermally. For this purpose, the semiconductor layer can be heated, e.g., to approximately 200°C or more, e.g., to approximately 300°C or more, e.g., to approximately 400°C or more, e.g., to approximately 500°C or more.

[0124] According to one exemplary implementation, a substrate is coated with the semiconductor material (also referred to as a semiconductor layer), or the substrate consists entirely of the semiconductor material. The substrate can be, for example, a semiconductor substrate (e.g., a semiconductor wafer). The substrate and the semiconductor material (e.g., the semiconductor layer) can differ from each other, for example, in their crystal structure, doping level, chemical composition, semiconductor material, thickness, or similar characteristics.

[0125] It can be understood that the chemical composition of the functional layer, e.g., its coating material, does not necessarily have to be identical to the target material. For example, a so-called co-PVD can be performed, in which, to illustrate, two interpenetrating PVD processes are carried out, which together provide a mixture as the coating material. Alternatively, the functional layer can consist of a stack of several layers that differ from each other in their chemical composition, e.g., in the proportion of a component (e.g., boron) of the target material(s). According to an exemplary implementation of co-PVD, the target material is converted into a first gaseous phase, and an additional target material (e.g.,Silicon) is converted into a second gaseous phase, which then interpenetrate to form a gaseous mixture (also called mixing), forming the functional layer (then also called the mixed layer). The chemical composition of the functional layer is then, for example, a function of the rate at which the target material is converted into the first gaseous phase and the rate at which the additional target material is converted into the second gaseous phase, e.g., a ratio of these rates to each other (also called the rate ratio). If the PVD is performed using sputtering, the co-PVD is also called co-sputtering, in which the target materials are atomized using a plasma.

[0126] It can also be understood that reactive gas need not necessarily be supplied only as a molecular gas, but can alternatively or additionally be provided, at least partially, by means of a gaseous phase into which a solid target material is transferred. It can further be understood that the chemical reaction to the (e.g., first) reaction product does not necessarily have to take place in the gaseous phase, but can alternatively or additionally take place in the functional layer.

[0127] Fig.1B illustrates a coating process using PVD (e.g. sputtering) according to various embodiments 100b in a schematic process diagram, preferably set up according to embodiments 100a, wherein the first reaction product (also referred to as main product) and the second reaction product (also referred to as by-product) are shown.

[0128] The coating process may involve converting the target material into a gaseous phase 232, e.g., using plasma. The gaseous phase 232 may contain the major element 202 (also referred to as the first chemical element) and the minor element 204 (also referred to as the second chemical element), e.g., in atomic and / or ionized form. Furthermore, the gaseous phase 232 can be exposed to a reactive gas 214, e.g., molecular oxygen or atoms and / or ions thereof, with which the main element 202 chemically reacts to form a main product 254 (e.g., boron oxide) 171 and with which the minor element 204 chemically reacts to form a minor product 252 (e.g., carbon oxide) 173. The chemical reaction 171 may, for example, hardly take place in the gas volume, but mainly at surfaces (e.g., of the target and / or the substrate), which favors the conservation of momentum (e.g., a three-particle collision may occur).An exemplary implementation of reactive gas 214 contains or consists of oxygen. In this case, the main product 254 is an oxide of the main element 202, and the by-product 252 is an oxide of the minor element 204. If the main element is boron (B), the main product 254 is an oxide of boron (also called boron oxide), e.g., B. a If the minor element is carbon (C), the byproduct 252 is an oxide of carbon (also called carbon oxide), e.g., carbon dioxide and / or carbon monoxide. As an alternative to boron, another dopant from the boron group can also be used for positive doping (p-doping) of silicon (Si), for example, as a semiconductor material. However, negative doping of silicon is also possible, e.g., by using a dopant from group V5.

[0129] The coating process (e.g., according to Example 10 or Example 11) further involves forming a functional layer 220 containing the main element 202 (also referred to as the first chemical element), e.g., the dopant and / or in a chemical compound as the main product of the main element 202 with the reactive gas. Alternatively or additionally, the by-product 252 (e.g., carbon oxide) can be gaseous, making it a volatile material. This inhibits (e.g., prevents) the by-product 252 from being incorporated into the functional layer 220. For example, the functional layer 220 can contain the main product 254, e.g., a weight fraction of less than 10% of the main product 254.

[0130] An exemplary implementation of the main element 202 is boron. The main product 254 can then, for example, contain or consist of boron trioxide. Alternatively or additionally, the main element can be a pure substance and / or the main product can be electrically insulating.

[0131] The by-product can be removed from the coating process, e.g., by means of a vacuum pump, which provides a vacuum to which the target material (e.g., the coating process) is exposed. Fig. 2A illustrates a coating process by PVD (e.g., sputtering) according to various embodiments 200a in a schematic process diagram, preferably configured according to embodiments 100a to 100b. The coating process can include coating a substrate 102 with the main product to form the functional layer 220.

[0132] As a result of the coating process, a coated substrate is obtained, which, for example, has a semiconductor adjacent to the functional layer 220. An exemplary implementation of the substrate has a solar cell precursor or at least a pn junction (also referred to as a semiconductor junction). For example, the functional layer can contain the main product, e.g., consist of it or be in a mixture with the semiconductor (or a chemical compound thereof) of the substrate.

[0133] The coated substrate comprises the substrate and the functional layer 220 formed on it. Furthermore, the semiconductor material of the substrate can be doped (e.g., according to Example 12). For this purpose, the coated substrate can be heated (also referred to as a heating process), e.g., by at least 10 Kelvin (K), e.g., by at least 50 K, e.g., by at least 100 K, e.g., by at least 200 K, e.g., by at least 500 K. The heating stimulates a transport 301 (e.g., by diffusion, which is also referred to as a diffusion process) of the main element into the substrate, e.g., into its semiconductor material.

[0134] If the semiconductor material is silicon (or more generally has a valence of 4), the main element can be a chemical element from the 3rd main group, e.g. boron.

[0135] In a practical example, the functional layer 220 can be used as a diffusion source in the fabrication of a solar cell (also referred to as the solar cell manufacturing process). The coated substrate can be heated to a temperature in the range of approximately 800°C to approximately 1050°C using a heating process (e.g., a high-temperature step), which stimulates a diffusion process. The substrate can be held at this temperature for a period of approximately 5 minutes to approximately 30 minutes. During this time, the diffusion process can occur, in which the dopant (e.g., boron) diffuses from the functional layer (e.g., the BSG) into the substrate, for example, into an adjacent silicon layer of the substrate or into a silicon wafer as the substrate.

[0136] Fig -2B illustrates a coated substrate as a result of a method and / or use according to various embodiments 200b in a schematic perspective view, which is preferably arranged according to embodiments 100a to 200a.

[0137] The process can include: doping a semiconductor layer 1502 of the substrate, which, for example, borders the functional layer (not shown), using the functional layer, e.g., with the first chemical element of the functional layer. The semiconductor layer doped in this way can be used, for example, as a contact layer or for producing a contact layer doped with the first chemical element, and / or for producing a passivating layer (also called a passivation layer). In the following, reference is made to the contact layer 1502, whereby the described properties of the contact layer 1502 can also apply analogously to the doped semiconductor layer.

[0138] The contact layer 1502 can provide an upper surface of the substrate 102, e.g., its top surface. Alternatively or additionally, the contact layer 1502 can be contacted by means of a metal, e.g., by means of a solder.

[0139] The substrate 102 can optionally have two layers 102a, 102b (e.g., semiconductor layers), of which a first layer 102a is in physical contact with the contact layer 1502 and / or a second layer 102b. The first layer 102a can be positioned between the contact layer 1502 and the second layer 102b. The first layer 102a and the contact layer 1502 can have the same doping polarity. Alternatively or additionally, the first layer 102a can have a lower doping level than the contact layer 1502.

[0140] The second layer 102b and the contact layer 1502 can differ in the polarity of their doping. The second layer 102b and the first layer 102a can also differ in the polarity of their doping. A semiconductor junction can be provided, for example, by means of the two layers 102a and 102b.

[0141] The substrate 102 can, for example, have the semiconductor junction (e.g. a pn junction) whose interface may, for example, be laterally extended, i.e., extend in the substrate plane.

[0142] Optionally, the contact layer 1502 can be a selective contact layer. The selective contact layer can be configured (e.g., electron-conducting or hole-conducting) such that it only allows charge carriers of exactly one polarity to pass through (positively or negatively charged), or at least is configured to be more conductive for charge carriers of a first (e.g., positive) polarity than for charge carriers of a second (e.g., negative) polarity.

[0143] For example, substrate 102 may contain a solar cell or be formed from one.

[0144] Fig. 3 illustrates a coating process using PVD (e.g. sputtering) according to various embodiments 300 in a schematic process diagram, preferably set up according to embodiments 100a to 200b.

[0145] The method can include: atomizing a semiconductor material 514t as an additional target material. The atomization of the semiconductor material 514t can be carried out using an additional target 514 made from the additional target material. The DC voltage can, for example, be supplied or applied between the target 504 and the additional target 514 and / or be inverted several times successively.

[0146] In other words, the sputtering of the target material 504t (e.g. provided by a first sputtering target 504) and the sputtering of the semiconductor material 514t (e.g. provided by a second sputtering target 514) can take place simultaneously (then also referred to as co-sputtering).

[0147] The semiconductor material 514t, as an additional target material, can optionally form a semiconductor layer as a functional layer, incorporating the sputtered target material (or at least boron) into the formed semiconductor layer. For this purpose, the sputtered semiconductor material (i.e., its gas phase 352) and the sputtered target material (i.e., its gas phase 354) can be mixed together, e.g., during their flight phase.

[0148] Optionally, the semiconductor material 514t, or the second sputtering target, can be doped, for example, with an additional dopant and / or p-doped. This can reduce the consumption of the first target material 504t. Co-sputtering can, for example, make it possible to perform sputtering in a process gas (i.e., an atmosphere) that is free of dopants and / or inert. To illustrate, a gas (process gas) can be supplied that is free of an additional dopant. For example, sputtering can be performed without the addition of a dopant gas.

[0149] Optionally, co-sputtering can feature: influencing (e.g., by controlling and / or regulating) the concentration of the dopant (also referred to as dopant concentration or doping level) in the functional layer. This influencing can be achieved, for example, by changing the operating point of sputtering the second target material. The influencing can be based, for example, on a measurement representing a chemical composition of the functional layer and / or the plasma. Alternatively, instead of co-sputtering, spatially separated vapor clouds 352 and 354 can be used, between which the substrate oscillates, resulting in stacking.The resulting stack can have several pairs of layers arranged one above the other (not shown), each pair having a first layer formed by means of the target material 504t and a second layer formed by means of the additional target material 514t.

[0150] Fig. 4A and Fig. 4B each illustrate a processing arrangement (also referred to as a vacuum processing arrangement) according to various embodiments 400a, 400b in a schematic cross-sectional view or side view, preferably set up according to embodiments 100a to 300.

[0151] According to various embodiments, a processing arrangement can include a vacuum chamber 802, for example, for coating a substrate 102 and / or doping its coating 102 by means of a coating process (e.g., a sputtering process). Furthermore, the processing arrangement can include a transport device 108 as an exemplary substrate holding device for transporting the substrate 102 along a transport path 111p through the vacuum chamber 802. The processing arrangement can also include at least one (i.e., one or more than one) coating device 704, for example, a sputtering device. The sputtering device 704 can, for example, be configured to atomize at least one (i.e., one or more than one) target material towards the transport path 111p and / or the transport surface 111f.

[0152] According to various embodiments, the processing arrangement can include a vacuum pump arrangement 814 (comprising at least one main vacuum pump and / or a rough vacuum pump). The vacuum pump arrangement 814 can be configured to extract a gas (e.g., the by-product and / or a process gas) from the vacuum chamber 802, so that a vacuum (i.e., a pressure less than 0.3 bar) and / or a pressure in the range of approximately 10 3 millibar (mbar) to approximately 10 7 mbar (in other words, high vacuum) or a pressure smaller than high vacuum, e.g., less than approximately 10 7 The process gas can be provided or can be provided at mbar (in other words, ultra-high vacuum). It can consist of a working gas (e.g., an inert gas) and optionally a reactive gas, or a gas mixture of several working gases and several optional reactive gases.

[0153] According to various embodiments, the processing arrangement can include a gas supply 702. The process gas can be supplied to the vacuum chamber 802 via the gas supply 702 to form a process atmosphere within the vacuum chamber 802. The process pressure can be established by an equilibrium of process gas, which is supplied via the gas supply 702 and extracted by the vacuum pump arrangement 814. According to various embodiments, the reactive gas can comprise at least one of the following: hydrogen, water (gaseous, e.g., water vapor), oxygen, nitrogen, hydrogen sulfide, methane, gaseous hydrocarbons, fluorine, chlorine, or another gaseous material. Alternatively or additionally, the working gas can comprise or be composed of an inert gas, such as a noble gas, e.g., argon. The reactive gas can exhibit a higher chemical reactivity than the working gas, e.g., with respect to the coating material.The reactive gas can contain, for example, (e.g., molecular) oxygen and / or (e.g., molecular) hydrogen, or be composed of these. Alternatively, the process gas can be inert.

[0154] According to various embodiments, the processing arrangement can include a control device 1802, which can be coupled (shown in dashed lines) to one or more components of the processing arrangement for controlling and / or regulating an operating point in the vacuum chamber 802. For example, the vacuum chamber 802 can be configured such that the operating point (the process conditions) within the vacuum chamber 802 can be set or regulated, e.g., during coating, e.g., by means of the control device 1802.

[0155] For example, the gas supply 702 and / or the vacuum pump arrangement 814 can be controlled and / or regulated by means of the control device 1802, e.g. according to a target operating point. In this case, the target operating point can, for example, represent a parameter of the atmosphere inside the vacuum chamber 802 (i.e., the process atmosphere), e.g. its chemical composition, pressure and / or spatial distribution.

[0156] According to various embodiments, the transport device 108 according to embodiment 400a can have an unwind roller 1002a for unwinding a ribbon-shaped substrate 1102 in the direction of the coating area 706. Furthermore, the transport device 108 of the processing arrangement can have a winding roller 1002b for winding up the ribbon-shaped substrate 102, which is transported from the direction of the coating area 706. Optionally, the substrate transport device 108 of the processing arrangement can have a plurality of transport rollers 320, which define a (e.g., simply or multiply curved) transport path 111p (or a correspondingly simply or multiply curved transport surface 111f) along which the ribbon-shaped substrate 102 is transported between the unwind roller 1002a and the winding roller 1002b past the plasma formation area 502.

[0157] A ribbon-shaped substrate 102 (ribbon substrate) can comprise or be formed from a film, a nonwoven fabric, a tape, and / or a woven fabric. For example, a ribbon-shaped substrate 102 can comprise or be formed from a metal tape, a metal foil, a plastic tape (polymer tape), and / or a plastic film (polymer film). Alternatively, the transport device 108 according to embodiment 400b can have a plurality of transport rollers 320, which are configured for transporting a plate-shaped substrate 102. The plate-shaped substrate 102 can be transported, for example, resting on the transport rollers 320 and / or placed in a substrate carrier 1110. The plate-shaped substrate 102 can, for example, comprise a wafer or another semiconductor substrate.

[0158] Furthermore, the processing arrangement can include a transport drive 1602, which is coupled to at least some of the plurality of transport rollers 320 and optionally to the unwind roller 1002a and the rewind roller 1002b. For example, the transport drive 1602 can be coupled to the rollers 320, 1002a, and 1002b by means of chains, belts, or gears. The transport rollers 320 and the transport drive 1602 can be part of the substrate transport device 108.

[0159] The following are supplementary work examples that refer to what has been described above and shown in the figures, including reference to carbon as an exemplary minor element, and what is described here can apply to one or more minor elements, which do not necessarily have to be carbon.

[0160] According to Working Example 1, e.g., an exemplary implementation of co-sputtering, boron carbide is sputtered as the target material using a plasma, so that a first gaseous phase (also referred to as the first gas phase) containing boron and carbon spreads towards the substrate. Simultaneously, silicon or silicon oxide is sputtered as an additional target material, so that a second gaseous phase (also referred to as the second gas phase) spreads towards the substrate, containing silicon. The first and second gaseous phases interpenetrate each other, forming a mixture exposed to oxygen as the reactive gas. The reactive gas reacts with the boron to form boron oxide, with the silicon to form silicon oxide (e.g., silicon dioxide), and with carbon to form carbon oxide. The boron oxide and silicon oxide are deposited on the substrate, forming a layer 220 of BSG.The carbon oxide is removed from the process, e.g. by means of the vacuum pump, so that it is not incorporated into layer 220.

[0161] According to working example 2, the oxygen of the atomized silicon oxide is used as a reactive gas (or alternatively) enriched with molecular oxygen, which reacts with the boron to form boron oxide.

[0162] According to working example 3, the target material is atomized (also known as sputtering) using a direct current (also known as DC sputtering). If the additional target material contains silicon, it can be doped, at least with the first chemical element (e.g., boron) or with a dopant from the same group as the first chemical element. Doping the silicon increases the electrical conductivity of the additional target material and thus facilitates sputtering with a direct current.

[0163] According to working example 4, co-sputtering of the target material containing boron and the additional target material containing silicon and optionally doped with boron is carried out.

[0164] According to working example 5, a boron dopant for the formation of boron sputtering compound (BSC) is provided using boron carbide as the target material (e.g., B₄C), which can be provided as a sputtering target. Boron carbide (e.g., B₄C) can be thermally sprayed, which facilitates target fabrication. According to working example 6, B₄C as the target material and silicon as an additional target material are co-sputtered with the addition of molecular oxygen, which is chemically reactive, allowing, for example, the deposition of a layer of BSC. The CO₂ or CO₂ formed from the carbon of the B₄C is volatile and is removed from the vacuum chamber by the vacuum system. Optionally, sputtering is performed using a DC voltage applied to the target material and / or without the use of an AC voltage in the radio frequency (RF) range.Generally, boron carbide is available in various B-to-C ratios, of which B4C is particularly suitable because it can be thermally sprayed, has sufficient electrical conductivity, and a low carbon content. Preferably, the target contains less carbon (e.g., based on at%, i.e., the total amount) than boron.

[0165] According to working example 7, reactive sputtering (e.g., with the addition of oxygen) is performed using a double magnetron with two targets, e.g., in bipolar operating mode. In bipolar operating mode, a DC voltage can be applied between the two targets, which is reversed (e.g., inverted) according to a predefined clock signal and / or a controlled duty cycle. This causes each target to operate alternately as an anode and cathode, which facilitates sputtering. One of the two targets is made of the target material (e.g., boron carbide), and the other is made of the additional target material (e.g., silicon) and optionally doped.

[0166] According to working example 8, reactive sputtering (e.g., with the addition of oxygen) is carried out using a double magnetron, which has a first target made of B₄C and a second target made of boron-doped Si (also referred to as Si:B). For example, the proportion of boron in the second target can be in the range of approximately 0.1 ppm (parts per million) to approximately 1 ppm. Using the duty cycle as a control variable, the rate ratio between Si₂O₃ and B₂O₃ can be influenced, and consequently, the boron content in the deposited layer (e.g., mixed layer), e.g., its BSG, can be adjusted.

[0167] According to working example 9, co-sputtering with Si:B and B4C is carried out as a reactive process with the addition of molecular oxygen, sequentially and / or by means of separate control loops.

[0168] According to working example 10, the ratio of B to Si does not need to be adjusted during the coating process, but is known as a specification, for example. Then, sputtering can be carried out on a target made of silicon borosilicate (SIBC) as the target material, which has a Si : B ratio according to the specification. A silicon borosilicate target can be produced by spraying a mixture of Si and B4C, which is cost-effective.

[0169] According to Working Example 11, the target material is used to form a layer of borosilicate glass (BSG), which is used for the fabrication of a semiconductor device, such as a solar cell. Optionally, the layer and / or differently doped areas of the semiconductor device can be structured, for example, using a laser process to locally inject the BSG into the underlying silicon wafer and increase the doping concentration there. This can be used, for example, to fabricate a selective emitter for a solar cell, such as a TOPCon solar cell (solar cell with tunnel oxide passivated contact). Alternatively or additionally, a laser-assisted etching process can be performed on the borosilicate glass.

[0170] According to working example 12 (e.g. set up according to one of working examples 1 to 11), B4C is used as the target material, which is favorable for sputtering and contributes little carbon.

[0171] According to Working Example 13 (e.g., set up according to one of Working Examples 1 to 12), the proportion of carbon from the target material transferred into the layer is reduced by means of oxygen. This can be achieved by varying the chemical composition of the plasma and / or the pressure to which the plasma is subjected. For example, with increasing oxygen partial pressure to which the plasma is exposed, the rate at which carbon and oxygen chemically react with each other, e.g., to form CO2 and / or CO, increases. Consequently, the proportion of carbon in the layer is reduced.

[0172] According to Working Example 14 (e.g., set up according to any of Working Examples 1 to 13), the layer has a smaller carbon-to-boron ratio than the target material. For example, the carbon-to-boron ratio Tv of the target material is Tv = 0.25. For example, the carbon-to-boron ratio Sv of the layer is Sv < 0.2, e.g., Sv < 0.1, e.g., Sv < 0.01, e.g., Sv < 0.001. This applies analogously to a minor element other than carbon. According to Working Example 15 (e.g., set up according to any of Working Examples 1 to 14), a boron-doped silicon oxide layer (e.g., having or consisting of borosilicate glass - BSG) is formed using a boron carbide target and a boron-doped silicon target. The silicon oxide layer has a thickness in the range of approximately 10 nm to approximately 100 nm (e.g., approximately 40 nm). The boron content of the boron-doped silicon oxide layer is approximately 3.5% by weight.and is adjusted by means of the duty cycle (as a control variable) between the boron carbide target and a boron-doped silicon target. Alternatively or additionally, the carbon content of the boron-doped silicon oxide layer is adjusted by means of the chemical composition (as a control variable) and / or the pressure (as a control variable) to which the plasma is exposed.

[0173] According to Working Example 16 (e.g., set up according to one of Working Examples 1 to 15), a boron-doped silicon oxide layer (e.g., containing or consisting of borosilicate glass - BSG) is formed on a silicon layer. In a subsequent high-temperature step (e.g., a diffusion process), the silicon layer (e.g., a silicon wafer) is heated to a temperature in the range of approximately 900°C to approximately 1050°C for a duration in the range of approximately 5 minutes to approximately 30 minutes to allow the boron to diffuse from the boron-doped silicon oxide layer into the silicon layer.

[0174] According to working example 17 (e.g. set up according to one of working examples 1 to 16), a boron-doped silicon oxide layer (e.g. having or consisting of borosilicate glass - BSG) is formed which has less carbon than boron or is free of carbon.

[0175] According to Working Example 18 (e.g., set up according to one of Working Examples 1 to 17), a chemical compound of a dopant (e.g., boron) of a semiconductor material with a minor element having the same valence as the semiconductor material is used as a target material for forming a layer (e.g., by means of a plasma), preferably over (e.g., on) the semiconductor material, by means of which the semiconductor material is doped with the dopant, wherein the target material is preferably exposed to a reactive gas (e.g., oxygen), e.g., by means of which a plasma is formed to which the target material is exposed and / or by means of which the layer is formed. The reactive gas is, for example, configured to react with the minor element to form a gaseous reaction product (e.g., under standard conditions and / or in a vacuum).

[0176] According to Working Example 19 (e.g. set up according to one of Working Examples 1 to 18), plasma formed by means of a reactive gas is used to stimulate a chemical reaction of the reactive gas with a minor element contained in a target material.

[0177] According to Working Example 20 (e.g., set up according to any of Working Examples 1 to 19), a plasma generated by a reactive gas is used to bind a minor element to the reactive gas that forms the plasma. The resulting layer then contains, for example, no minor element (e.g., carbon), meaning the ratio of the minor element to boron is zero and therefore smaller than that of the target material. According to Working Example 21 (e.g., set up according to any of Working Examples 1 to 20), the plasma is used to reduce the ratio between the minor element and boron in a stream of material emitted by a target material exposed to the plasma; a layer is formed by means of a result (e.g., a chemical composition of the stream as a result) of the reduction.For this purpose, the plasma is preferably free of nitrogen, which inhibits the formation of carbon nitride, so that it can be removed from the plasma as an oxide.

Claims

Patent claims 1. Using a target material containing boron and at least one minor element to form a layer (220) having a smaller ratio of the at least one minor element to boron than the target material, by means of a plasma to which the target material is exposed.

2. Use according to claim 1, wherein the minor element is carbon.

3. Method according to claim 1 or 2, wherein a chemical compound of boron with the at least one minor element is used as the target material, wherein the chemical compound is preferably a boron carbide.

4. Method according to any one of claims 1 to 3, wherein oxygen is supplied to the plasma and / or wherein the plasma contains excited and / or ionized oxygen.

5. Method according to claim 4, wherein a chemical reaction of the minor element, which is carbon, with oxygen is carried out to form a gaseous reaction product under standard conditions and / or under vacuum, which is removed from the plasma.

6. Use according to any one of claims 1 to 5, wherein the layer (220) comprises a glass which contains boron, preferably an oxide of boron.

7. Use according to any one of claims 1 to 6, wherein the plasma has more oxygen than nitrogen, preferably free of nitrogen.

8. Use according to any one of claims 1 to 7, wherein the layer contains less boron than of the at least one minor element.

9. Use according to any one of claims 1 to 8, wherein the layer (220) has more oxygen than of the at least one minor element and / or is free of the at least one minor element.

10. Use according to any one of claims 1 to 9, wherein the layer (220) has more oxygen than boron.

11. Use according to any one of claims 1 to 10, wherein the layer (220) is formed over, preferably on, a semiconductor material or a chemical compound of the semiconductor material.

12. Use according to claim 11, wherein the layer (220) is used to dope the semiconductor material with boron.

13. Use according to claim 12, wherein a result of doping the semiconductor material with boron is used to produce a semiconductor device, which preferably has the result.

14. Use according to claim 13, wherein the semiconductor device is a solar cell which preferably uses the result as an emitter.

15. Use according to any one of claims 11 to 14, wherein the layer (220) further comprises the semiconductor material.

16. Use according to any one of claims 11 to 15, wherein the semiconductor material is silicon and is preferably provided by means of silicon oxide.

17. Use according to any one of claims 11 to 16, wherein the layer (220) has less boron as semiconductor material.

18. Use according to any one of claims 11 to 17, wherein the layer (220) is formed by means of an additional target material which comprises the semiconductor material and / or is exposed to the plasma.

19. Use according to claim 18, wherein the additional target material is doped with boron.

20. Use according to any one of claims 1 to 19, wherein a DC voltage, preferably pulsed DC voltage, is applied to the target by means of which the plasma is formed; and / or wherein the plasma is exposed to a magnetic field.

21. Use according to any one of claims 1 to 20, wherein the layer (220) further comprises silicon, preferably silicon oxide.

22. Using a processing arrangement for using the target material according to any one of claims 1 to 21.

23. Use according to claim 22, comprising the processing arrangement: • a vacuum chamber (802), • a sputtering device (704) arranged in the vacuum chamber (802), which contains the target material and is set up to form the layer (220) by means of the plasma to which the target material is exposed; • a substrate holder (108) which is configured to hold a substrate in the vacuum chamber (802) for the formation of the layer on the substrate.

24. Method which implements the use according to any one of claims 1 to 23.

25. Processing arrangement comprising: • a vacuum chamber (802), • a sputtering device (704) arranged in the vacuum chamber (802), comprising a target material comprising boron and at least one minor element, for forming a layer (220) having a smaller ratio of the at least one minor element to boron than the target material, by means of a plasma to which a target material is exposed; • a substrate holder (108) configured to hold a substrate in the vacuum chamber (802).

26. Using a chemical compound consisting of a dopant of a semiconductor material with a minor element having the same valence as the semiconductor material as a target material for forming a layer by which the semiconductor material is doped with the dopant, wherein the target material for forming the layer is exposed to a reactive gas by means of which a plasma is formed.

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