78 results about "Dislocation free" patented technology

Structures and methods of manufacturing are disclosed of dislocation free stressed channels in bulk silicon and SOI (silicon on insulator) CMOS (complementary metal oxide semiconductor) devices by gate stress engineering with SiGe and/or Si:C. A CMOS device comprises a substrate of either bulk Si or SOI, a gate dielectric layer over the substrate, and a stacked gate structure of SiGe and/or Si:C having stresses produced at the interfaces of SSi(strained Si)/SiGe or SSi/Si:C in the stacked gate structure. The stacked gate structure has a first stressed film layer of large grain size Si or SiGe over the gate dielectric layer, a second stressed film layer of strained SiGe or strained Si:C over the first stressed film layer, and a semiconductor or conductor such as p(poly)-Si over the second stressed film layer.

A method for forming dislocation-free strained silicon thin film includes the step of providing two curved silicon substrates. One substrate is curved by the presence of silicon dioxide on a back surface. The other substrate is curved by the presence of a silicon nitride layer. One of the substrates is subject to hydrogen implantation and the two substrates are bonded to one another in an annealing process. The two substrates are separated, thereby leaving a layer of strained silicon on a front side of one of the substrates. A back side layer of silicon dioxide or silicon nitride is then removed to restore the substrate to a substantially planar state. The method may be employed to form dislocation-free strained silicon thin films. The films may be under tensile or compressive strain.

A method of forming a virtually defect free lattice mismatched nanoheteroepitaxial layer is disclosed. The method includes forming an interface layer on a portion of a substrate. A plurality of seed pads are then formed by self-directed touchdown by exposing the interface layer to a material comprising a semiconductor material. The plurality of seed pads, having an average width of about 1 nm to 10 nm, are interspersed within the interface layer and contact the substrate. An epitaxial layer is then formed by lateral growth of the seed pads over the interface layer.

A dislocation-free high quality template with relaxed lattice constant, fabricated by spatially restricting misfit dislocation(s) around heterointerfaces. This can be used as a template layer for high In composition devices. Specifically, the present invention prepares high quality InGaN templates (In composition is around 5-10%), and can grow much higher In-composition InGaN quantum wells (QWs) (or multi quantum wells (MQWs)) on these templates than would otherwise be possible.

A SIMOX semiconductor structure is provided that may include a silicon substrate, a doped glass layer formed on the silicon substrate by ion implantation and a silicon layer formed on the silicon substrate. Ion implantation may form the doped glass layer to reduce the dislocation density of the silicon layer.

The invention discloses germanium-doped directionally solidified casting monocrystalline silicon, which contains boron, gallium or phosphorus with the concentration of between 1*10 and 1*10/cm and germanium with the concentration of between 1*10 and 5*10/cm. The invention also discloses a preparation method for the germanium-doped directionally solidified casting monocrystalline silicon, which comprises the following steps: placing polycrystalline silicon, the germanium and an electroactive doping agent on a dislocation-free monocrystalline silicon block paved on the bottom of a crucible; completely melting the polycrystalline silicon, the germanium and the doping agent and partially melting the dislocation-free monocrystalline silicon block by thermal field regulation; and performing directional solidification by heat exchange, and using a part of unmelted dislocation-free momocrystalline silicon block as a seed crystal to induce to grow the germanium-doped casting monocrystalline silicon from bottom to top. The product has strong mechanical strength and long minority carrier lifetime, can be used for preparing a high efficiency wafer solar cell, and greatly reduces the production cost.

The invention discloses a method for preparing a (110) float zone silicon crystal. The key point of the technical scheme is that: 1, in the seeding technology, by controlling and adjusting the descending speed of a lower shaft and adjusting the power, the seeding neck diameter is controlled in a range from 2 to 6 mm, wherein the seeding neck diameter is more than or equal to 1.5 times the diameter of a single crystal; 2, in the shouldering technology, by controlling and adjusting the descending speed and rotating speed of the lower shaft and the descending speed and rotating speed of an upper shaft and adjusting the power, the shouldering angle is 50+/-5 degrees; and 3, in the ending technology, the ending length is more than 1.2 times the diameter of the single crystal, and the minimum tail diameter is less than or equal to 5mm. The method overcomes the defects that the (110) silicon single crystal prepared by the conventional direct pulling method has high impurity content and cannot meet the requirement on the silicon single crystal of a high-efficiency solar cell, and successfully prepares a low-impurity content and long-service life (110) dislocation-free float zone silicon crystal by a floating zone method, wherein the (110) float zone silicon crystal has the dislocation density of less than or equal to 500 units/cm<2> and the minority carrier lifetime of more than or equal to 300us, and meets the requirement of a silicon material for preparing the high-efficiency solar cell.

This invention is directed to a method for the production of a dislocation-free silicon single crystal by the Czochralski method. This method attains growth of the main body part of the dislocation-free silicon single crystal by immersing a seed crystal in a melt of silicon and then pulling the seed crystal without recourse to the necking. The seed crystal thus used is a dislocation-free silicon single crystal. The horizontal maximum length of the part of the seed crystal being immersed in the melt at the time of completing the immersion of the seed crystal in the melt is not less than 5 mm. The immersing rate of the seed crystal in the melt is not more than 2.8 mm/min and the part of the seed crystal to be immersed in the melt is a crystal as grown.

A method of forming a stressed thin film on a substrate includes the steps of depositing a thin film of silicon on a first substrate and transforming the first substrate into a porous substrate. The porous substrate containing the thin film of silicon is then transformed into a stressed state such that at least a portion of the stress is transferred to the thin film. The thin film may be under compressive stress or tensile stress. For example, volumetric expansion of the porous substrate imparts tensile stress to the thin film while volumetric contraction of the porous substrate imparts compressive stress to the thin film. The porous substrate containing the stressed thin film of silicon is then bonded to a second substrate. The porous substrate is removed so as to deposit the stressed thin film of silicon to the second substrate.

A method for forming CMOS devices includes masking a first portion of a tensile-strained silicon layer of a SOI substrate, doping a second portion of the layer outside the first portion and growing an undoped silicon layer on the doped portion and the first portion. The undoped silicon layer becomes tensile-strained. Strain in the undoped silicon layer over the doped portion is relaxed by converting the doped portion to a porous silicon to form a relaxed silicon layer. The porous silicon is converted to an oxide. A SiGe layer is grown and oxidized to convert the relaxed silicon layer to a compressed SiGe layer. Fins are etched in the first portion from the tensile-strained silicon layer and the undoped silicon layer and in the second portion from the compressed SiGe layer.

The invention discloses nitrogen-doped directionally solidified casting monocrystalline silicon, which contains boron, gallium and phosphorus with the concentration of between 1*10 and 1*10/cm and nitrogen with the concentration of between 1*10 and 5*10/cm. The invention also discloses a preparation method for the nitrogen-doped directionally solidified casting monocrystalline silicon, which comprises the following steps: using cheap nitrogen to replace expensive argon to be taken as protective gas; and taking partial unmelted dislocation-free monocrystalline silicon blocks as a seed crystal to perform directional solidification and casting on the monocrystalline silicon. The preparation method reduces the production cost of the monocrystalline silicon and improves the mechanical strength of the monocrystalline silicon. A casting monocrystalline silicon product obtained by the method has high mechanical strength, can be used for preparing a high-efficiency wafer solar cell, and greatly reduces the production cost.

A method capable of securely pulling up a heavy single crystal is described. Using an apparatus comprising a crucible for storing a molten material for a single crystal; a heater for heating the molten material; means for pulling up the single crystal to grow by bringing a seed crystal in contact with the surface of the molten material in the crucible; and a flow-regulating member surrounding the single crystal at the growth area for shielding the heat of radiation and for regulating inert gas flow, the method comprises the following steps of: setting the distance between the lower end of the flow-regulating member and the surface of the molten material to be a first distance D1 when the seed crystal comes into contact with the surface of the molten material in said crucible; forming the single crystal at the neck portion; thereafter setting the distance between the lower end of the flow-regulating member and the surface of the molten material to be a second distance D2 where D1 (mm)>D2 (mm); and forming the single crystal at the shoulder portion and subsequently forming the single crystal at the body portion. A dislocation-free single crystal having a heavy weight can be produced with a high crystal quality, and the method is applicable to various operation modes at which the apparatus is operated under various conditions of crystal growth.

There is disclosed a method of producing a silicon monocrystal which comprises preparing a silicon seed crystal having a sharp tip end, and melting down a part of the silicon seed crystal from a tip end to a position having a predetermined thickness, followed by performing a necking operation to form a tapered necking part and a neck portion, and subsequently pulling a monocrystal ingot after increasing a diameter, wherein said part to be melted down is a part from a tip end to a position in which a thickness is twice as large as the diameter of the neck portion to be formed or more; said necking operation is performed in such a way that a tapered necking part is formed at an early stage by pulling a crystal with gradually decreasing the diameter to a minimum diameter of 5 mm or more, and then a neck portion is formed, subsequently the monocrystal ingot is pulled with increasing a diameter. There can be provided a method of producing a silicon monocrystal ingot which enables growing of monocrystal ingot without lowering rate of success in making a crystal dislocation free in the case that a thick neck is formed, and thereby improves productivity of a heavy silicon monocrystal having a large diameter.

The invention discloses an N-type casting monocrystalline silicon with a uniform doping resistivity and a preparation method thereof. The preparation method comprises the following steps of: paving dislocation-free materials of monocrystalline silicon blocks at the bottom of a crucible; then placing a polycrystalline silicon material, a phosphorus doping agent and gallium into the crucible; raising temperature and fusing the monocrystalline silicon material, the phosphorus doping agent, the gallium and a part of materials of monocrystalline silicon blocks close to the polycrystalline silicon; and growing a monocrystalline silicon body by using a casting method. According to the monocrystalline silicon with the uniform doping resistivity, the resistivity of about 90% N-type phosphorus doping phosphorus doping cast ingots can be controlled in the range of 1.0-2.0 omega.cm, therefore, the utilization rate of the N-type monocrystalline silicon in the process of manufacturing a solar cell is effectively improved, the manufacturing cost of the solar cell is remarkably lowered, the preparation method is simple to operate and easy to popularize and use in the photovoltaic industry.

The invention relates to a method for preparing the crystallization rate of crystal orientation monocrystal silicon (110), which is characterized in that: a seed crystal of which the crystal orientation deviates an angle of X from the (110) direction is cut by adopting a monocrystal (110) or (100); and the seed crystal is subjected to seeding, and the seeding length is kept by more than 12 centimeters, wherein the X is between 1 and 9 degrees. In the method, a crystal axis of the seed crystal (110) deviates an angle X from the growth direction, dislocation can be discharged completely in the seeding process, and the led crystal with the crystal orientation (110) can grow in a dislocation-free mode, so the crystallization rate can be improved, and the yield can be ensured.

The application belongs to the technical field of production of monocrystalline silicon and particularly relates to a method for preparing the monocrystalline silicon by using a czochralski method. The method comprises the following steps: after a silicon material is melt in a single crystal furnace, heating power of the single crystal furnace decreases rapidly; after a temperature controller controls the temperature in the single crystal furnace to be stabilized, a seed crystal makes contact with the liquid level and then necking is carried out; after necking reaches a certain height, dislocation-free shouldering is performed and a crystal grows; the heating power of the single crystal furnace is gradually reduced step-by-step and shoulder rotation is started to perform when the crystal grows to reach the target diameter. By using the method, the growth cycle of the single crystal can be shortened by about 100 minutes and the success rate of necking is improved by 40 to 50 percent. Inaddition, the method has the advantages that necking temperature can be quickly found out, dislocation of the grown crystal is reduced, the growth cycle of single crystal is shortened and the contacttime between the silicon material and a quartz crucible is reduced, so that influence of silicon impurities is reduced as well as the success rate of necking and the quality of the single crystal areimproved.