Selective etching of materials containing silicon and germanium with improved surface purity.

Abstract

An exemplary semiconductor processing method may include providing an oxygen-containing precursor to a processing area in a semiconductor processing chamber. A substrate may be housed within the processing area. A first layer of a silicon-germanium-containing material, a second layer of a silicon-germanium-containing material, and a layer of silicon-containing material may be arranged on the substrate. The method may include bringing the substrate into contact with the oxygen-containing precursor. This contact may oxidize at least a portion of the second layer of the silicon-germanium-containing material. The method may include providing a first etchant precursor to the processing area and bringing the substrate into contact with the first etchant precursor. This contact may selectively etch the first layer of the silicon-germanium-containing material. The method may include providing a second etchant precursor to the processing area. The method may include bringing the substrate into contact with the second etchant precursor. This contact may etch a portion of the silicon-containing material layer.

Description

Technical Field

[0001] Cross - reference to Related Applications

[0001] This application claims the benefit and priority of U.S. Patent Application No. 18 / 375,207, titled "SELECTIVE ETCHING OF SILICON - AND - GERMANIUM - CONTAINING MATERIALS WITH INCREASED SURFACE PURITIES", filed on September 29, 2023, which is hereby incorporated by reference in its entirety.

[0002]

[0002] This technology relates to semiconductor processing and devices. More specifically, this technology relates to selectively etching materials containing silicon and germanium in vertical structures.

Background Art

[0003]

[0003] Integrated circuits are enabled by a process of creating complex patterned layers of materials on a substrate surface. To create patterned materials on a substrate, a controlled method for removing the exposed materials is required. Chemical etching is used for various purposes, including transferring a photoresist pattern to a lower layer, thinning a layer, or reducing the lateral dimensions of features already present on a surface. In many cases, it is desirable to perform an etching process that etches one material faster than other materials, for example, to facilitate a pattern transfer process. Such an etching process is said to be selective to the first material. As a result of the diversity in materials, circuits, and processes, etching processes having selectivity to various materials have been developed.

[0004]

[0004] Etching processes may be called wet or dry, depending on the materials used in the process. Wet HF etching selectively removes silicon oxide more than other dielectrics and materials. However, wet processes have difficulty penetrating some confined trenches and can sometimes deform the remaining material. Dry etching, performed with localized plasma formed within the substrate processing area, can penetrate more confined trenches and can minimize deformation of delicate remaining structures. However, localized plasmas can damage the substrate by generating electric arcs when they discharge.

[0005]

[0005] Therefore, there is a need for improved systems and methods that can be used to manufacture high-quality devices and structures. This technology addresses these and other needs. [Overview of the project]

[0006]

[0006] An exemplary semiconductor processing method may include providing an oxygen-containing precursor to a processing area of ​​a semiconductor processing chamber. A substrate may be housed in the processing area. On the substrate, a first layer of a material containing silicon and germanium, a second layer of a material containing silicon and germanium, and a layer of silicon-containing material may be arranged. The method may include bringing the substrate into contact with the oxygen-containing precursor. This contact may oxidize at least a portion of the second layer of the material containing silicon and germanium. The method may include providing a first etchant precursor to the processing area. The method may include bringing the substrate into contact with the first etchant precursor. This contact may selectively etch the first layer of the material containing silicon and germanium. The method may include providing a second etchant precursor to the processing area. The method may include bringing the substrate into contact with the second etchant precursor. This contact may etch a portion of the layer of silicon-containing material.

[0007]

[0007] In some embodiments, the first layer of the silicon-germanium-containing material may be characterized by a first germanium concentration. The second layer of the silicon-germanium-containing material may be characterized by a second germanium concentration. The first germanium concentration may be lower than the second germanium concentration. The oxygen-containing precursor may be diatomic oxygen (O2) or vapor (H2O), or may contain them. The method may include forming a plasma emission of the oxygen-containing precursor. The second etchant precursor may be a fluorine-containing precursor. The method may include providing a hydrogen-containing precursor together with the second etchant precursor. A portion of the silicon-containing material layer may be characterized by a thickness of about 7 nm or less. The pressure in the processing area may be maintained at about 30 Torr or less. Contact with the first etchant precursor may etch the first layer of the silicon-germanium-containing material with a selectivity of about 40:1 or more for the second layer of the silicon-germanium-containing material. The temperature within the processing area can be maintained at approximately 150°C or higher. Contact between the substrate and the oxygen-containing precursor, contact between the substrate and the first etchant precursor, and contact between the substrate and the second etchant precursor can be performed on a single mainframe.

[0008]

[0008] Some embodiments of the present technology may encompass a semiconductor processing method. The method may include providing an oxygen-containing precursor to a processing area in a semiconductor processing chamber. A substrate may be housed in the processing area. On the substrate, a first layer of a silicon-germanium-containing material, a second layer of a silicon-germanium-containing material, and a layer of silicon-containing material may be arranged. The first layer of the silicon-germanium-containing material may be characterized by a lower germanium concentration than that of the second layer of the silicon-germanium-containing material. The method may include contacting the substrate with the oxygen-containing precursor. This contact may oxidize at least a portion of the second layer of the silicon-germanium-containing material. The method may include providing a first fluorine-containing precursor to the processing area. The method may include contacting the substrate with the first fluorine-containing precursor. The contact may etch the first layer of the silicon-germanium-containing material with respect to the second layer of the silicon-germanium-containing material with a selectivity of about 40:1 or more. This method may include providing a second fluorine-containing precursor to a processing area. This method may include forming a plasma emission of the second fluorine-containing precursor. This method may include bringing a substrate into contact with the second fluorine-containing precursor. This contact may etch a layer of silicon-containing material between approximately 2 nm and 5 nm.

[0009]

[0009] In some embodiments, the first layer of the silicon-germanium-containing material may be characterized by a germanium concentration of about 35 atomic percent or less. The second layer of the silicon-germanium-containing material may be or contain doped silicon-germanium-containing material. The oxygen-containing precursor may be or contain diatomic oxygen (O2) or vapor (H2O). The method may include forming a plasma emission of H2O. After contacting the substrate with the second fluorine-containing precursor, the surface of the silicon-containing material layer may be characterized by a germanium concentration of about 1.5 atomic percent or less.

[0010]

[0010] Some embodiments of the present technology may encompass semiconductor processing methods. The method may include providing an oxygen-containing precursor to a processing area of ​​a semiconductor processing chamber. The oxygen-containing precursor may be diatomic oxygen (O2) or vapor (H2O), or may contain either. A substrate may be housed in the processing area. On the substrate, a first layer of a silicon-germanium-containing material, a second layer of a silicon-germanium-containing material, and a layer of silicon-containing material may be arranged. The first layer of the silicon-germanium-containing material may be characterized by a lower germanium concentration than that of the second layer of the silicon-germanium-containing material. The method may include bringing the substrate into contact with the oxygen-containing precursor. This contact may oxidize at least a portion of the second layer of the silicon-germanium-containing material. The method may include providing a first fluorine-containing precursor to the processing area. The method may include bringing the substrate into contact with the first fluorine-containing precursor. This contact may selectively etch the first layer of the silicon-germanium-containing material. This method may include providing a second fluorine-containing precursor and a hydrogen-containing precursor to a processing area. This method may include forming plasma emissions of the second fluorine-containing precursor and the hydrogen-containing precursor. This method may include bringing a substrate into contact with the plasma emissions of the second fluorine-containing precursor and the hydrogen-containing precursor. This contact may etch a layer of silicon-containing material between approximately 2 nm and approximately 5 nm.

[0011]

[0011] In some embodiments, the temperature within the processing area can be maintained at about 200°C or higher. After contacting the substrate with the second fluorine-containing precursor, the surface of the silicon-containing material layer can be characterized by a germanium concentration of about 1.0 atomic% or less.

[0012]

[0012] Such technologies may offer numerous advantages over conventional systems and techniques. For example, the process can selectively oxidize one silicon-germanium-containing material with respect to another silicon-germanium-containing material before etching. Furthermore, selective oxidation may allow selective etching of the unoxidized silicon-germanium-containing material with respect to the oxidized silicon-germanium-containing material. Finally, subsequent etching of the silicon-containing material can reduce and / or remove germanium residue in the final device. These and other embodiments, along with many of their advantages and features, will be described in more detail below in conjunction with the accompanying figures.

[0013]

[0013] The nature and advantages of the disclosed technology can be further understood by referring to the remainder of this specification and the drawings. [Brief explanation of the drawing]

[0014] [Figure 1] This shows a top view of one embodiment of an exemplary processing system according to an embodiment of this technology. [Figure 2A] A schematic cross-sectional view of an exemplary processing chamber according to an embodiment of this technology is shown. [Figure 2B] Figure 2A shows a detailed view of a part of the processing chamber according to an embodiment of this technology. [Figure 3] This shows a bottom view of an exemplary shower head according to an embodiment of this technology. [Figure 4] The following are exemplary steps of the method according to an embodiment of this technology. [Figures 5A-5D] This shows a cross-sectional view of a substrate being processed according to an embodiment of this technology. [Modes for carrying out the invention]

[0015]

[0020] Some of the drawings are included as schematic diagrams. These diagrams are for illustrative purposes only and should not be considered to scale unless specifically stated. Furthermore, these diagrams are schematic and presented to aid understanding. They may not include all features and information compared to a realistic representation, and may include extraneous or exaggerated elements for illustrative purposes.

[0016]

[0021] In the attached drawings, similar components and / or features may have the same reference numeral. Furthermore, various components of the same type may be distinguished according to their reference numerals by letters that distinguish between similar components. Where only a first reference numeral is used herein, its description may apply to any similar component having the same first reference numeral, regardless of the letters mentioned above.

[0017]

[0022] In the transition to gate-all-around (GAA) transistors, many processing steps are changed from those of more conventional fin field-effect (FinFET) transistors. Furthermore, as the size of the structure continues to shrink, the thickness of the material layers decreases, and the aspect ratio of memory holes and other structures sometimes increases dramatically.

[0018]

[0023] During the GAA process, alternating layers of materials, such as alternating layers of silicon-containing material and silicon- and germanium-containing material, are deposited on the substrate. When forming transistors, memory holes or trenches may be formed through the alternating layers of materials. During the GAA process, the silicon- and germanium-containing material may be recessed from within the memory holes or trenches to form materials that function as nanowires / nanosheets. Subsequently, one or more materials, including another silicon- and germanium-containing material, may be formed within the recesses and / or memory holes or trenches.

[0019]

[0024] Since some GAA transistors have similar materials, it may become increasingly difficult to selectively remove one material relative to another. For example, multiple silicon-containing materials including materials containing a plurality of silicon and germanium can be used for GAA processing. In some processes, it may be desirable to remove a material containing one silicon and germanium, such as a silicon and germanium-containing nanowire, from a material containing epitaxial silicon and germanium and other silicon-containing materials. Conventional techniques have struggled to selectively remove a material containing one silicon and germanium compared to a material containing another silicon and germanium. Non-selective removal can result in unwanted etching of some materials, such as a material containing epitaxial silicon and germanium. Further, due to the difficulty in selectively removing a material containing one silicon and germanium relative to a material containing another silicon and germanium, some germanium residues may remain after removal. The presence of germanium residues can potentially degrade the final device performance.

[0020]

[0025] This technology overcomes these problems by performing selective oxidation before etching silicon-germanium-containing materials, such as silicon-germanium-containing nanowires. Selective oxidation can preferentially oxidize silicon-germanium-containing materials characterized by higher germanium concentrations, such as materials containing epitaxial silicon and germanium. Oxidized silicon-germanium-containing materials may be more resistant to etching than unoxidized silicon-germanium-containing materials. Therefore, subsequent etching processes to remove silicon-germanium-containing materials characterized by lower germanium concentrations can selectively remove materials with lower concentrations compared to materials with higher concentrations. Thus, the etching process of this technology can successfully remove one silicon-germanium-containing material while retaining other silicon-germanium-containing materials in addition to other silicon-containing materials. Furthermore, by subsequent etching of a portion of the silicon-containing material with germanium residue, undesirable germanium residue can be reduced and / or removed, improving the final device performance.

[0021]

[0026] The remaining disclosures, as is customary, identify specific etching processes that utilize the disclosed technology, but it will be readily apparent that the systems and methods are equally applicable to etching processes that may occur in the described chambers. Therefore, this technology should not be considered limited to use in etching processes or chambers. Furthermore, while exemplary chambers are described to provide the basis for this technology, it should be understood that the technology can be applied to substantially any semiconductor processing chamber capable of enabling the described operation.

[0022]

[0027] FIG. 1 shows a top view of one embodiment of a processing system 100 of a deposition chamber, an etching chamber, a baking chamber, and a curing chamber according to an embodiment. In this figure, a pair of front-opening unified pods (FOUPs) 102 provide substrates of various sizes. These substrates are received by a robotic arm 104, placed in a low-pressure holding area 106, and then disposed in one of the substrate processing chambers 108a-f positioned within tandem sections 109a-c. A second robotic arm 110 can be used to transport the substrate wafer from the holding area 106 to the substrate processing chambers 108a-f and vice versa. Each substrate processing chamber 108a-108f can be equipped to perform several substrate processing steps, including dry etching processes described herein, in addition to cyclic layer deposition (CLD), atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etching, pre-cleaning, degassing, orientation, and other substrate processing.

[0023]

[0028] The substrate processing chambers 108a-f can include one or more system components for depositing, annealing, curing, and / or etching a dielectric film on a substrate wafer. In one configuration, two pairs of processing chambers (e.g., 108c-d and 108e-f) may be used to deposit a dielectric material on the substrate, and a third pair of processing chambers (e.g., 108a-b) may be used to etch the deposited dielectric. In other configurations, all three pairs of chambers (e.g., 108a-108f) may be configured to etch a dielectric film on the substrate. One or more of the processes described can be performed in a chamber separate from the manufacturing system shown in various embodiments. It will be appreciated that further configurations of deposition chambers, etching chambers, annealing chambers, and curing chambers for dielectric films are being considered in system 100.

[0024]

[0029] Figure 2A shows a cross-sectional view of an exemplary processing chamber system 200 having a plasma generation region partitioned within the processing chamber. While etching a film (e.g., titanium nitride, tantalum nitride, tungsten, silicon, polysilicon, silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbide, etc.), the processing gas can flow into the first plasma region 215 through the gas inlet assembly 205. A remote plasma system (RPS) 201 may optionally be included in the system to process the first gas. The gas then moves through the gas inlet assembly 205. The inlet assembly 205 may include two or more different gas supply channels, and a second channel (not shown), if included, may bypass the RPS 201.

[0025]

[0030] A cooling plate 203, a faceplate 217, an ion suppressor 223, a shower head 225, and a pedestal 265 on which a substrate 255 is placed are shown, each of which may be included according to the embodiment. The pedestal 265 may have heat exchange channels through which a heat exchange fluid flows to control the temperature of the substrate. The heat exchange channels may be operated to heat and / or cool the substrate or wafer during the processing steps. The wafer support platter of the pedestal 265 includes aluminum, ceramic, or a combination thereof, and may further be resistance-heated to reach relatively high temperatures (e.g., from about 100°C or less to about 1100°C or more) using an integrated resistance heating element.

[0026]

[0031] The faceplate 217 may be pyramidal, conical, or another similar structure, narrower at the top and widening towards the bottom. The faceplate 217 may further be flat as shown and include a plurality of through-channels used for distributing the processing gas. Depending on the use of the RPS 201, the plasma generating gas and / or plasma excited species may pass through the plurality of holes in the faceplate 217 shown in Figure 2B to be delivered more uniformly within the first plasma region 215.

[0027]

[0032] An exemplary configuration may include a gas inlet assembly 205 opening into a gas supply region 258 separated from the first plasma region 215 by the faceplate 217, so that a gas / seed flows into the first plasma region 215 through a hole in the faceplate 217. Structural and operational features may be selected to prevent large-volume backflow of plasma from the first plasma region 215 into the supply region 258, the gas inlet assembly 205, and the fluid supply system 210. The faceplate 217 (or the conductive upper part of the chamber) and the showerhead 225 are shown with an insulating ring 220 positioned between their features, thereby allowing an AC potential to be applied to the faceplate 217 relative to the showerhead 225 and / or the ion suppressor 223. The insulating ring 220 can be positioned between the faceplate 217 and the showerhead 225 and / or the ion suppressor 223, thereby enabling the formation of a capacitively coupled plasma (CCP) within the first plasma region. Furthermore, a baffle (not shown) can be placed within the first plasma region 215 or otherwise coupled with the gas inlet assembly 205, influencing the flow of fluid into the region through the gas inlet assembly 205.

[0028]

[0033] The ion suppressor 223 may include a plate or other shape that defines multiple openings throughout the structure. This is configured to suppress the movement of ion-charged species escaping from the first plasma region 215, while allowing uncharged neutral or radical species to pass through the ion suppressor 223 and enter the activated gas delivery region between the suppressor and the showerhead. In embodiments, the ion suppressor 223 may comprise a perforated plate with various opening configurations. These uncharged species may include highly reactive species that are transported through the openings along with a less reactive carrier gas. As described above, the movement of ion species through the openings can be reduced, and in some cases, completely suppressed. By controlling the amount of ion species passing through the ion suppressor 223, it is advantageous to improve control over the gas mixture that comes into contact with the underlying wafer substrate, and as a result, improve control over the deposition and / or etching properties of the gas mixture. For example, by adjusting the ion concentration of the gas mixture, the etching selectivity of the gas mixture (e.g., SiGe) can be improved. x :SiO x Etching ratio, SiGe x The Si etching ratio, etc., can be significantly altered. In alternative embodiments where deposition is carried out, it is also possible to change the balance between conformal deposition and flowable deposition of the dielectric material.

[0029]

[0034] Multiple openings in the ion suppressor 223 may be configured to control the passage of active gas (i.e., ionic species, radical species, and / or neutral species) through the ion suppressor 223. For example, the aspect ratio (i.e., diameter relative to length of hole) and / or shape dimensions of the holes can be controlled to reduce the flow rate of ionic charged species in the active gas passing through the ion suppressor 223. The holes in the ion suppressor 223 may include tapered portions facing the plasma region 215 and cylindrical portions facing the showerhead 225. The cylindrical portions may be shaped and dimensionally formed to control the flow rate of ionic species passing to the showerhead 225. An adjustable electrical bias can be applied to the ion suppressor 223, which is an additional means of controlling the flow rate of ionic species passing through the suppressor.

[0030]

[0035] The ion suppressor 223 can function to reduce or eliminate the amount of ionic species that travel from the plasma generation region to the substrate. Uncharged neutral species and radical species can further pass through the ion suppressor openings to react with the substrate. It should be noted that complete removal of ionic species from the reaction region around the substrate may not be achieved depending on the embodiment. In certain cases, ionic species are intended to reach the substrate to carry out etching and / or deposition processes. In such cases, the ion suppressor may help control the concentration of ionic species in the reaction region to a certain level that aids the process.

[0031]

[0036] The showerhead 225, in combination with the ion suppressor 223, can enable the plasma present in the first plasma region 215 to avoid direct excitation of gases in the substrate processing region 233, while also allowing excited species to move from the chamber plasma region 215 into the substrate processing region 233. In this way, the chamber can be configured to prevent the plasma from coming into contact with the substrate 255 being etched. This advantageously protects various complex structures and films patterned on the substrate. These complex structures and films can be damaged, displaced, or distorted if they come into direct contact with the generated plasma. In addition, if the plasma can come into contact with the substrate or approach the substrate level, the rate at which the material can be etched increases. Therefore, by keeping the plasma at a distance from the substrate, the exposed areas of the material can be further protected.

[0032]

[0037] The processing system may further include a power supply 240 electrically coupled to the processing chamber. The power supply 240 provides power to a faceplate 217, an ion suppressor 223, a showerhead 225, and / or a pedestal 265 to generate plasma in a first plasma region 215 or processing region 233. The power supply may be configured to deliver a tunable amount of power to the chamber depending on the processing being performed. Such a configuration may allow for the use of a tunable plasma in the processing being performed. Unlike remote plasma units, which are often presented with an on or off function, a tunable plasma may be configured to deliver a specific amount of power to the plasma region 215. This may enable the development of specific plasma properties, thereby allowing for the isolation of precursors in a specific manner and the enhancement of etching profiles generated by these precursors.

[0033]

[0038] Plasma can be ignited in either the chamber plasma region 215 above the showerhead 225 or the substrate processing region 233 below the showerhead 225. For example, plasma may be present in the chamber plasma region 215 to generate radical precursors from the influx of fluorine-containing precursors or other precursors. Typically, an AC voltage in the radio frequency (RF) range can be applied between the conductive upper part of the processing chamber, such as the faceplate 217, and the showerhead 225 and / or ion suppressor 223 to ignite the plasma in the chamber plasma region 215 during deposition. The RF power source can generate a high RF frequency of 13.56 MHz, but can also generate other frequencies, either alone or in combination with the 13.56 MHz frequency.

[0034]

[0039] Figure 2B is a detailed diagram of features affecting the distribution of the processing gas through the faceplate 217. As shown in Figures 2A and 2B, the intersection of the faceplate 217, the cooling plate 203, and the gas inlet assembly 205 defines the gas supply region 258. The processing gas can be delivered to the gas supply region 258 from the gas inlet assembly 205. The gas fills the gas supply region 258 and can flow through the opening 259 in the faceplate 217 to the first plasma region 215. The opening 259 may be configured to guide the flow substantially in one direction. This allows the processing gas to flow into the processing region 233, but partially or completely prevents backflow into the gas supply region 258 after crossing the faceplate 217.

[0035]

[0040] The gas distribution assembly used in the processing chamber section 200, such as the showerhead 225, is also referred to as a dual-channel showerhead (DCSH) and is shown in more detail in the embodiment described in Figure 3. The dual-channel showerhead allows for the isolation of etchants outside the processing area 233 and provides an etching process that results in limited interaction with chamber components and each other before being delivered into the processing area.

[0036]

[0041] The showerhead 225 may include an upper plate 214 and a lower plate 216. The plates can be joined together to define a space 218 between them. By joining the plates, a first fluid channel 219 can be provided through the upper and lower plates, and a second fluid channel 221 can be provided through the lower plate 216. The formed channels may be configured to provide fluid access from the space 218 through the lower plate 216 only, through the second fluid channel 221, and the first fluid channel 219 may be fluidically isolated from the space 218 between the plates and the second fluid channel 221. The space 218 may be fluidically accessible through the sides of the showerhead 225.

[0037]

[0042] Figure 3 is a bottom view of a showerhead 325 for use in a processing chamber according to an embodiment. The showerhead 325 may correspond to the showerhead 225 shown in Figure 2A. The through-holes 365, shown in the figure of the first fluid channel 219, may have multiple shapes and configurations to control and influence the flow of precursor through the showerhead 225. The small holes 375, shown in the figure of the second fluid channel 221, are distributed almost evenly on the surface of the showerhead, even between the through-holes 365. Compared to other configurations, these small holes 375 may help to result in a more uniform mixing as the precursor flows out of the showerhead.

[0038]

[0043] The chamber described above may be used to perform exemplary methods, including etching methods. Figure 4 shows exemplary steps of Method 400 according to embodiments of the Art. Prior to the first step of the Method, the substrate may be treated in one or more ways before being placed in the processing area of ​​the chamber in which Method 400 may be performed. For example, alternating layers of material may be formed on the substrate, and then one or more memory holes or trenches may be formed through the alternating layers. The alternating layers may contain any number of materials, and may include alternating layers of silicon-containing material and silicon-germanium-containing material. The remainder of the disclosure describes silicon-containing material and silicon-germanium-containing material, but other known materials used in these two layers may be used instead of one or more layers. One of the materials in the alternating layers, such as the silicon-germanium-containing material, may be recessed. Oxygen-containing material may be formed in the recess, and then spacer material may be formed thereafter. Furthermore, epitaxial material, such as a second silicon-germanium-containing material, may be formed in one or more memory holes or trenches. Some or all of these processes may be performed within a chamber or system tool as described above, or within different chambers on the same system tool that include the chamber in which the process of method 400 is performed.

[0039]

[0044] Method 400 may include, in an optional step 405, providing a processing precursor, such as a pretreatment precursor or a pre-etching precursor, to a semiconductor processing chamber. In some embodiments, an inert precursor may be supplied together with the processing precursor. An exemplary chamber may be the aforementioned chamber 200, which may include either or both of the RPS unit 201 or the first plasma region 215. Plasma may be formed in an optional step 410, which may form plasma emissions of the processing precursor. The substrate may come into contact with the processing precursor, or, if formed, plasma emissions of the processing precursor, in an optional step 415. Contact in the optional step 415 may remove native oxides present on the first layer of silicon-germanium material and the second layer of silicon-germanium material on the substrate. The process of developing the structure may include removing or etching one or more materials. To enhance selectivity during removal or etching, Method 400 may include, in step 420, providing an oxygen-containing precursor to a processing area; in an optional step 425, forming a plasma emission of the oxygen-containing precursor; and in step 430, contacting a substrate with the oxygen-containing precursor or its plasma emission. The contact in step 430 can oxidize at least a portion of a second layer of a silicon-germanium-containing material, which may be an epitaxial silicon-germanium-containing material. Following a certain amount of oxidation, Method 400 may include, in step 435, providing a first etchant precursor to a processing area; in an optional step 440, optionally forming a plasma emission of the first etchant precursor; and in step 445, contacting a substrate with the first etchant precursor. The contact in step 445 can selectively etch a first layer of a silicon-germanium-containing material, which may be a silicon-germanium-containing material nanowire for a GAA transistor.Method 400 may include, in step 435, providing a second etchant precursor to a processing area; in an optional step 455, optionally forming plasma emissions of the second etchant precursor; and in step 460, bringing a substrate into contact with the second etchant precursor. The second etchant precursor can remove a portion of a silicon-containing material, such as a silicon-containing material having germanium residue. Reducing and / or removing germanium residue can improve electron mobility, potentially leading to improved final device performance.

[0040]

[0045] Method 400 may involve selectively oxidizing one silicon-germanium material with respect to another silicon-germanium material. One silicon-germanium material may be selectively oxidized to a greater extent than another silicon-germanium material depending on the germanium concentration of the material. The silicon-germanium material to be oxidized may be characterized by a higher germanium concentration and therefore may be oxidized preferentially over the other silicon-germanium material. By selectively oxidizing one silicon-germanium material with respect to another silicon-germanium material, a subsequent etching process can selectively remove the silicon-germanium material that remains less oxidized or less oxidized than the other silicon-germanium material. Thus, GAA transistors, for example, lower germanium-containing silicon and germanium-containing nanowires, can be selectively etched or released with respect to higher germanium-containing silicon and germanium-containing epitaxial materials. Method 400 may enable the selective oxidation of one silicon-germanium-containing material with respect to another silicon-germanium-containing material, followed by selective removal.

[0041]

[0046] The precursors provided to the processing area of ​​Method 400 in the optional step 405 may include processing precursors such as pretreatment precursors or etching precursors, and optionally inert precursors. Exemplary processing precursors may be hydrogen-containing precursors, nitrogen-containing precursors, or combinations thereof, which may flow into the processing area. Hydrogen-containing precursors may include, for example, molecular hydrogen (H2), ammonia (NH3), or other hydrogen-containing precursors used or useful in semiconductor processing. Nitrogen-containing precursors may include, for example, molecular nitrogen (N2), ammonia (NH3), or any other nitrogen-containing precursors used or useful in semiconductor processing. In some embodiments, the processing precursors may be provided together with inert precursors. Inert precursors may include, for example, argon, helium, xenon, or other rare, inert, or useful precursors. Inert precursors may be used to dilute the processing precursors or to assist in distributing the processing precursors throughout the processing area.

[0042]

[0047] When formed in an optional step 410, the plasma emissions of the processed precursor and inert precursor (if present) may be generated at a plasma output of approximately 5,000 W or less, and may also be generated at approximately 4,750 W or less, approximately 4,500 W or less, approximately 4,250 W or less, approximately 4,000 W or less, approximately 3,750 W or less, approximately 3,500 W or less, approximately 3,250 W or less, approximately 3,000 W or less, approximately 2,750 W or less, approximately 2,500 W or less, approximately 2,250 W or less, approximately 2,000 W or less, approximately 1,750 W or less, approximately 1,500 W or less, approximately 1,250 W or less, approximately 1,000 W or less, approximately 750 W or less, approximately 500 W or less, approximately 250 W or less, or less.

[0043]

[0048] The substrate can be brought into contact with the plasma emissions of the processing precursor in an optional step 415 for a time sufficient to remove native oxides from the silicon and germanium-containing material. In embodiments, the duration may be about 3 seconds or more, about 5 seconds or more, about 10 seconds or more, about 20 seconds or more, about 30 seconds or more, about 40 seconds or more, about 50 seconds or more, about 1 minute or more, about 2 minutes or more, about 3 minutes or more, about 5 minutes or more, or longer. This duration is sufficient to remove about 85% or more of the native oxides from the silicon and germanium-containing material, and can remove about 90% or more, about 95% or more, about 97% or more, about 99% or more, about 99.9% or more, or all of the native oxides from the silicon and germanium-containing material.

[0044]

[0049] In some embodiments, method 400 may include, in step 420, providing an oxygen-containing precursor to the processing area of ​​a semiconductor processing chamber. In some embodiments, an inert precursor may be supplied together with the oxygen-containing precursor. The oxygen-containing precursor may be, for example, molecular oxygen (O2), vapor (H2O), hydrogen peroxide (H2O2), or any other oxygen-containing precursor used or useful in semiconductor processing, or may include these. The inert precursor may be, for example, argon, helium, xenon, or other dilute, inert, or useful precursor, or may include these. The inert precursor may be used to dilute the oxygen-containing precursor, which can further reduce the oxidation rate to control the oxidation and selectivity of the oxidation, or to help distribute the oxygen-containing precursor throughout the processing area. Furthermore, the flow rate ratio of the oxygen-containing precursor, and, if present, the inert precursor, may be adjusted to modulate the oxidation effect and / or oxidation selectivity of the oxygen-containing precursor.

[0045]

[0050] The flow rates of the oxygen-containing precursor and the inert precursor, if present, may be sufficient to selectively oxidize one silicon-germanium-containing material with respect to another silicon-germanium-containing material. In embodiments, the flow rate of the oxygen-containing precursor to the processing area may be about 1 sccm or more, about 10 sccm or more, about 50 sccm or more, about 100 sccm or more, about 250 sccm or more, about 500 sccm or more, about 1,000 sccm or more, about 1,500 sccm or more, about 2,000 sccm or more, about 2,500 sccm or more, about 3,000 sccm, about 3,500 sccm or more, about 4,000 sccm or more, or higher. In addition, the flow rate of the inert precursor capable of diluting and / or distributing the oxygen-containing precursor or its plasma emissions may be about 100 sccm or more, and may be about 250 sccm or more, about 500 sccm or more, about 750 sccm or more, about 1,000 sccm or more, about 2,500 sccm or more, about 5,000 sccm or more, about 7,500 sccm or more, about 10,000 sccm or more, or higher.

[0046]

[0051] In some embodiments, plasma ejecta of an oxygen-containing precursor may be generated in an optional step 425. As described above, plasma ejecta may be generated within the processing area. However, plasma ejecta may not be formed from the oxygen-containing precursor, and it is assumed that plasma-free or thermal oxidation may be performed. For example, if the oxygen-containing precursor is O2 or H2O, the plasma ejecta may oxidize all silicon- and germanium-containing materials on the substrate. Therefore, in subsequent etching to remove one silicon- and germanium-containing material from another silicon- and germanium-containing material, it may not be possible to etch any of the oxidized silicon- and germanium-containing materials. In embodiments in which plasma emissions of oxygen-containing precursors are formed, the plasma emissions of oxygen-containing precursors and inert precursors, if present, may be generated at a plasma output of approximately 5,000 W or less, and may be generated at approximately 4,750 W or less, approximately 4,500 W or less, approximately 4,250 W or less, approximately 4,000 W or less, approximately 3,750 W or less, approximately 3,500 W or less, approximately 3,250 W or less, approximately 3,000 W or less, approximately 2,750 W or less, approximately 2,500 W or less, approximately 2,250 W or less, approximately 2,000 W or less, approximately 1,750 W or less, approximately 1,500 W or less, approximately 1,250 W or less, approximately 1,000 W or less, approximately 750 W or less, approximately 500 W or less, approximately 250 W or less, or less. Compared to pre-treated precursors, plasma emissions of oxygen-containing precursors can be generated at lower plasma outputs. By generating post-processing plasma emissions at lower plasma power, oxidation can be better controlled, and impact / damage to the substrate and deposited materials thereon can be limited.

[0047]

[0052] Method 400 may include, in step 430, contacting a substrate with an oxygen-containing precursor or its plasma emission. The contact may continue for a time sufficient to oxidize at least one of a plurality of silicon and germanium-containing materials on the substrate. In embodiments, the duration may be about 3 seconds or more, about 5 seconds or more, about 10 seconds or more, about 20 seconds or more, about 30 seconds or more, about 40 seconds or more, about 50 seconds or more, about 1 minute or more, about 2 minutes or more, about 3 minutes or more, about 5 minutes or more, or longer. Similarly, the duration may be about 5 minutes or less, about 3 minutes or less, about 2 minutes or less, about 1 minute or less, about 50 seconds or less, about 40 seconds or less, about 30 seconds or less, about 20 seconds or less, about 10 seconds or less, about 5 seconds or less, about 3 seconds or less, or shorter.

[0048]

[0053] By bringing a substrate into contact with an oxygen-containing precursor, germanium and / or silicon in a silicon-germanium-containing material can combine with oxygen and oxidize a portion of the silicon-germanium-containing material. While not bound by any particular theory, it is believed that germanium can combine more readily with oxygen, and that silicon-germanium-containing materials with higher germanium concentrations can be oxidized more easily than adjacent silicon-germanium-containing materials with lower germanium concentrations. In addition, Si-Ge bonds in silicon-germanium-containing materials are more easily broken than Si-Si bonds in adjacent silicon-containing materials, and silicon-germanium-containing materials are thought to be more easily oxidized than adjacent silicon-containing materials. Furthermore, by operating in the temperature and / or pressure range described later, silicon-germanium-containing materials with higher germanium concentrations can be oxidized more easily.

[0049]

[0054] In step 435, method 400 may include providing a first etchant precursor to the processing area of ​​a semiconductor processing chamber. In some embodiments, an inert precursor may be supplied together with the first etchant precursor. The first etchant precursor may be a halogen-containing precursor or any other precursor capable of selectively etching materials containing silicon and germanium. The first etchant precursor may be, for example, diatomic fluorine (F2), nitrogen trifluoride (NF3), hydrogen fluoride (HF), or any other fluorine-containing precursor used or useful in semiconductor processing, or may include these. The inert precursor may be, for example, argon, helium, xenon, or any other rare, inert, or useful precursor, or may include these. The inert precursor may be used to dilute the first etchant precursor, which may further reduce the etching rate in order to control the etching rate and selectivity or to help distribute the first etchant precursor throughout the processing area. Furthermore, etching selectivity can be adjusted by adjusting the flow rate ratio between the first etchant precursor and, if present, the inert precursor.

[0050]

[0055] The flow rates of the first etchant precursor and inert precursor, if present, may be sufficient to selectively etch one silicon-germanium-containing material with another silicon-germanium-containing material. In embodiments, the flow rate of the first etchant precursor to the processing area may be about 1 sccm or more, about 10 sccm or more, about 50 sccm or more, about 100 sccm or more, about 250 sccm or more, about 500 sccm or more, about 1,000 sccm or more, about 1,500 sccm or more, about 2,000 sccm or more, about 2,500 sccm or more, about 3,000 sccm or more, about 3,500 sccm or more, about 4,000 sccm or more, or more. In addition, the flow rate of the inert precursor capable of diluting and / or distributing the first etchant precursor or its plasma emission may be about 100 sccm or more, and may be about 250 sccm or more, about 500 sccm or more, about 750 sccm or more, about 1,000 sccm or more, about 2,500 sccm or more, about 5,000 sccm or more, about 7,500 sccm or more, 10,000 sccm or more, or more.

[0051]

[0056] In some embodiments, the plasma ejecta of the first etchant precursor may be generated in an optional step 440. As described above, the plasma ejecta may be generated within the processing area. In the embodiment, the plasma emissions of the first etchant precursor and inert precursor may be generated at a plasma output of approximately 5,000 W or less, if present, and may be generated at approximately 4,750 W or less, approximately 4,500 W or less, approximately 4,250 W or less, approximately 4,000 W or less, approximately 3,750 W or less, approximately 3,500 W or less, approximately 3,250 W or less, approximately 3,000 W or less, approximately 2,750 W or less, approximately 2,500 W or less, approximately 2,250 W or less, approximately 2,000 W or less, approximately 1,750 W or less, approximately 1,500 W or less, approximately 1,250 W or less, approximately 1,000 W or less, approximately 750 W or less, approximately 500 W or less, approximately 250 W or less, or less.

[0052]

[0057] Method 400 may include, in step 445, contacting a substrate with a first etchant precursor or its plasma emission. The contact may continue for a time sufficient to etch at least one of a plurality of silicon and germanium-containing materials on the substrate. In embodiments, the duration may be about 3 seconds or more, about 5 seconds or more, about 10 seconds or more, about 20 seconds or more, about 30 seconds or more, about 40 seconds or more, about 50 seconds or more, about 1 minute or more, about 2 minutes or more, about 3 minutes or more, about 5 minutes or more, or longer. Similarly, the duration may be about 5 minutes or less, about 3 minutes or less, about 2 minutes or less, about 1 minute or less, about 50 seconds or less, about 40 seconds or less, about 30 seconds or less, about 20 seconds or less, about 10 seconds or less, about 5 seconds or less, about 3 seconds or less, or less.

[0053]

[0058] By bringing the substrate into contact with a first etchant precursor, materials containing unoxidized silicon and germanium can be selectively removed from other materials on the substrate that contain oxidized silicon and germanium. Although not bound by any particular theory, it is thought that materials containing oxidized silicon and germanium may be more resistant to the first etchant precursor than materials containing unoxidized silicon and germanium. Therefore, materials containing unoxidized silicon and germanium can be selectively removed compared to materials containing oxidized silicon and germanium. Thus, in GAA transistors, materials containing unoxidized silicon and germanium with lower germanium concentrations, such as SiGe nanowires, can be selectively removed from materials containing oxidized silicon and germanium with higher germanium concentrations, such as epitaxial SiGe materials.

[0054]

[0059] The contact in step 445 can etch one layer of the silicon-germanium material with a selectivity of about 40:1 or more to another layer of the silicon-germanium material. For example, an unoxidized layer of the silicon-germanium material can be etched with a selectivity of about 42:1 or more to an oxidized layer of the silicon-germanium material, for example, with a selectivity of about 44:1 or more, about 46:1 or more, about 48:1 or more, about 50:1 or more, about 52:1 or more, about 54:1 or more, about 56:1 or more, 58:1 or more, or higher.

[0055]

[0060] After selective etching of a material containing unoxidized silicon and germanium against other materials on a substrate, some germanium residue may remain on certain surfaces. For example, some germanium residue may be present on silicon-containing materials such as silicon nanowires. If left untreated or not removed from the surface of the silicon-containing material, the residue may affect the electron mobility of the final device. Therefore, the presence of germanium residue on silicon-containing materials, for example, can degrade the performance of the final device. This technology can address this problem by selectively removing a certain amount of silicon-containing material to reduce the presence of germanium residue.

[0056]

[0061] In step 450, method 400 may include providing a second etchant precursor to the processing area of ​​a semiconductor processing chamber. In some embodiments, a hydrogen-containing precursor and / or an inert precursor may be supplied together with the second etchant precursor. The second etchant precursor may be a halogen-containing precursor or any other precursor capable of selectively etching silicon-containing materials. The second etchant precursor may be, for example, diatomic fluorine (F2), nitrogen trifluoride (NF3), hydrogen fluoride (HF), carbon tetrafluoride (CF4), xenon difluoride (XeF2), or any other fluorine-containing precursor used or useful in semiconductor processing, or may include these. The hydrogen-containing precursor may be, for example, diatomic hydrogen (H2), ammonia (NH3), hydrocarbons, or any other hydrogen-containing precursor used or useful in semiconductor processing, or may include these. The inert precursor may be, for example, argon, helium, nitrogen, xenon, or any other rare, inert, or useful precursor, or may include these. An inert precursor may be used to dilute the second etchant precursor, which can further reduce the etching rate to control the etching rate and selectivity, or to help distribute the second etchant precursor throughout the processing area. Furthermore, the etching selectivity can be adjusted by adjusting the flow rate ratio of the second etchant precursor and, if present, the inert precursor.

[0057]

[0062] The flow rates of the second etchant precursor and inert precursor, if present, may be sufficient to selectively etch one silicon-germanium-containing material with respect to another silicon-germanium-containing material. In embodiments, the flow rate of the second etchant precursor to the processing area may be about 1 sccm or more, about 10 sccm or more, about 50 sccm or more, about 100 sccm or more, about 250 sccm or more, about 500 sccm or more, about 1,000 sccm or more, about 1,500 sccm or more, about 2,000 sccm or more, about 2,500 sccm or more, about 3,000 sccm or more, about 3,500 sccm or more, about 4,000 sccm or more, or higher. In addition, the flow rate of the inert precursor capable of diluting and / or distributing the second etchant precursor or its plasma emission may be about 100 sccm or more, and may be about 250 sccm or more, about 500 sccm or more, about 750 sccm or more, about 1,000 sccm or more, about 2,500 sccm or more, about 5,000 sccm or more, about 7,500 sccm or more, about 10,000 sccm or more, or more.

[0058]

[0063] In embodiments, the atomic flow ratio of hydrogen to fluorine may be greater than 1:1, about 1.2:1 or greater, about 1.4:1 or greater, about 1.6:1 or greater, about 1.8:1 or greater, about 2:1 or greater, about 4:1 or greater, or higher. In embodiments, a higher atomic flow ratio of hydrogen to fluorine may increase the selectivity for silicon. Some precursors may contain both fluorine and hydrogen, in which case the atomic flow rates of all components are included when calculating the atomic flow ratios described herein. Furthermore, the atomic flow ratio of argon or any other inert material to fluorine may be about 100:1 or greater, about 150:1 or greater, or about 200:1 or greater, or higher.

[0059]

[0064] In some embodiments, plasma ejecta of the second etchant precursor may be generated in an optional step 455. The plasma ejecta may be generated within the processing area or within the RPS. In the embodiment, the plasma emissions of the second etchant precursor and the hydrogen-containing precursor and / or inert precursor may, if present, be generated at a plasma output of about 5,000 W or less, and may be generated at about 4,750 W or less, about 4,500 W or less, about 4,250 W or less, about 4,000 W or less, about 3,750 W or less, about 3,500 W or less, about 3,250 W or less, about 3,000 W or less, about 2,750 W or less, about 2,500 W or less, about 2,250 W or less, about 2,000 W or less, about 1,750 W or less, about 1,500 W or less, about 1,250 W or less, about 1,000 W or less, about 750 W or less, about 500 W or less, about 250 W or less, or less.

[0060]

[0065] Method 400 may include, in step 460, contacting a substrate with a second etchant precursor or its plasma emissions. The contact may continue for a time sufficient to etch a portion of the silicon-containing material on the substrate. In embodiments, the duration may be about 3 seconds or more, about 5 seconds or more, about 10 seconds or more, about 20 seconds or more, about 30 seconds or more, about 40 seconds or more, about 50 seconds or more, about 1 minute or more, about 2 minutes or more, about 3 minutes or more, about 5 minutes or more, or longer. Similarly, the duration may be about 5 minutes or less, about 3 minutes or less, about 2 minutes or less, about 1 minute or less, about 50 seconds or less, about 40 seconds or less, about 30 seconds or less, about 20 seconds or less, about 10 seconds or less, about 5 seconds or less, about 3 seconds or less, or shorter durations may be preferred to remove only small amounts of silicon-containing material, such as silicon-containing material with germanium residue.

[0061]

[0066] The contact can etch silicon-containing material down to about 10 nm in size, while reducing germanium residue and preserving the silicon-containing material as much as possible. In the embodiment, the contact can etch silicon-containing material down to about 9 nm in size, for example, down to about 8 nm, 7 nm, 6 nm, 5 nm, 4 nm, 3 nm, 2 nm, or less, for example, between about 2 nm and 5 nm in size.

[0062]

[0067] The contact in step 445 can etch one layer of the silicon-containing material with a selectivity of about 40:1 or more compared to any other material on the substrate. For example, the silicon-containing material may be etched with a selectivity of about 50:1 or more compared to any other material on the substrate, for example, with a selectivity of about 60:1 or more, about 70:1 or more, about 80:1 or more, about 90:1 or more, about 100:1 or more, about 125:1 or more, about 150:1 or more, or higher.

[0063]

[0068] After contacting the substrate with the second etchant precursor, the surface of the silicon-containing material may be characterized by a germanium concentration of approximately 1.5 at.% or less, approximately 1.4 at.% or less, approximately 1.3 at.% or less, approximately 1.2 at.% or less, approximately 1.1 at.% or less, approximately 1.1 at.% or less, approximately 0.9 at.% or less, approximately 0.8 at.% or less, approximately 0.7 at.% or less, approximately 0.6 at.% or less, approximately 0.5 at.% or less, approximately 0.4 at.% or less, approximately 0.3 at.% or less, approximately 0.2 at.% or less, or lower.

[0064]

[0069] In the embodiment, steps 405-415 may be performed in the same semiconductor processing chamber as steps 420-430, or the substrate may be transferred to a second processing area of ​​a second semiconductor processing chamber in order to selectively oxidize a single silicon-germanium material on the substrate in steps 420-430. However, the second semiconductor processing chamber may be on the same processing system or mainframe (such as processing system 100) as the semiconductor processing chamber used in steps 405-415. In addition, steps 435-445 may be performed in the same semiconductor processing chamber as steps 405-415 and / or steps 420-430, or the substrate may be transferred to a third processing area of ​​a third semiconductor processing chamber in order to selectively etch a single silicon-germanium material on the substrate in steps 435-445. However, the third semiconductor processing chamber may be on the same processing system or mainframe (e.g., processing system 100) as the semiconductor processing chamber used in steps 405-415 and / or steps 420-430. Furthermore, steps 450-460 may be performed in the same semiconductor processing chamber as steps 405-415, steps 420-430, and / or steps 435-445, or the substrate may be transferred to a fourth processing area of ​​the fourth semiconductor processing chamber in order to selectively etch the silicon-containing material on the substrate in steps 450-460 to reduce and / or remove germanium residue. However, the fourth semiconductor processing chamber may be on the same processing system or mainframe (e.g., processing system 100) as the semiconductor processing chamber used in steps 405-415, steps 420-430, and / or steps 435-445. Therefore, the contact between the substrate and the pre-treated precursor, the contact between the substrate and the oxygen-containing precursor, the contact between the substrate and the first etchant precursor, and the contact between the substrate and the second etchant precursor can be performed on a single mainframe.

[0065]

[0070] Processing conditions may also affect the operation performed by Method 400 according to this technology and other etching methods. Depending on the embodiment, each step of Method 400 may be performed at a constant temperature, while in some embodiments, the temperature may be adjusted during different steps. For example, the temperature of the substrate, pedestal, or chamber may be maintained between about 25°C and about 500°C in embodiments. The temperature may also be maintained at temperatures below about 480°C, below about 460°C, below about 440°C, below about 420°C, below about 400°C, below about 380°C, below about 360°C, below about 350°C, below about 340°C, below about 330°C, below about 320°C, below about 310°C, below about 300°C, below about 280°C, below about 260°C, below about 240°C, below about 220°C, below about 200°C, or lower. In embodiments, the temperature may also be maintained at temperatures of approximately 100°C or higher, approximately 120°C or higher, approximately 140°C or higher, approximately 150°C or higher, approximately 160°C or higher, approximately 180°C or higher, approximately 200°C or higher, approximately 220°C or higher, approximately 240°C or higher, approximately 260°C or higher, approximately 280°C or higher, approximately 300°C or higher, approximately 320°C or higher, approximately 340°C or higher, approximately 360°C or higher, approximately 380°C or higher, approximately 400°C or higher, approximately 420°C or higher, approximately 440°C or higher, approximately 460°C or higher, approximately 480°C, approximately 500°C or higher, or higher. Temperature may affect the quality of the oxidation process, with higher temperatures potentially allowing for better oxidation of materials containing silicon and germanium. Higher temperatures may also produce greater reactivity between the etchant precursor and the material containing silicon and germanium. Similarly, lower temperatures may slow down the removal of materials containing silicon and germanium due to their lower reactivity. Therefore, in some embodiments, maintaining a temperature of about 150°C or higher may result in increased and better oxidation and / or removal of materials containing silicon and germanium.

[0066]

[0071] The pressure within the chamber can also affect the operation being performed, and in embodiments, the pressure within the semiconductor processing chamber may be maintained at pressures of about 1 Torr or higher, about 2 Torr or higher, about 3 Torr or higher, about 4 Torr or higher, about 5 Torr or higher, about 7.5 Torr or higher, about 10 Torr or higher, about 12.5 Torr or higher, about 15 Torr or higher, about 17.5 Torr or higher, about 20 Torr or higher, or higher. Each step of Method 400 may be performed at a constant pressure in embodiments, but in some embodiments, the pressure may be adjusted during different steps. In embodiments, a pressure of about 1 Torr or higher may result in stronger oxidation of one silicon-germanium-containing material compared to another silicon-germanium-containing material. Therefore, lower pressures may result in weaker oxidation and thus may require additional time for sufficient or desired oxidation. However, in order to maintain precise selectivity of oxidation, the pressure in the chamber may also be maintained at a pressure of about 30 Torr or less, and can be maintained at a pressure of about 28 Torr or less, about 26 Torr or less, about 24 Torr or less, about 22 Torr or less, about 20 Torr or less, about 18 Torr or less, about 16 Torr or less, about 14 Torr or less, about 12 Torr or less, about 10 Torr or less, or lower.

[0067]

[0072] Referring to Figures 5A to 5D, cross-sectional views of a structure 500 processed according to embodiments of the present technology are shown. As shown in Figure 5A, the structure 500 may include a substrate 505 having a plurality of laminated layers covering the substrate. The substrate 505 may be a silicon-containing material, a silicon-and-germanium-containing material, or other substrate material. The alternating layers of material may include materials suitable for GAA transistors, such as a silicon-containing material 510 alternating with a first silicon-and-germanium-containing material 515. The first silicon-and-germanium-containing material 515 is or may include a material that forms and / or removes recesses to generate nanowires / nanosheets within the GAA transistor. Although only seven layers of material are shown, the exemplary structure may include any number of layers. Memory holes or trenches may be defined through the laminated structure down to the level of the substrate 505. Memory holes or trenches may be defined by sidewalls that may consist of alternating layers of silicon-containing material 510 and the first silicon-and-germanium-containing material 515. After the first silicon-germanium-containing material 515 is recessed, an oxygen-containing material 520 and a spacer material 525 may be formed in the recess. As shown in Figure 5A, the oxygen-containing material 520 may be aligned with the silicon-containing material 510 and the first silicon-germanium-containing material 515 that define the recess. The spacer material 525 may then be deposited in the remaining area where the first silicon-germanium-containing material 515 was previously located. The second silicon-germanium-containing material 530 may then be formed in a memory hole or trench defined through the laminated structure.

[0068]

[0073] In the embodiment, the second silicon-germanium-containing material 530, which can be epitaxially grown, can be characterized by a higher germanium concentration than the first silicon-germanium-containing material 515. For example, the first silicon-germanium-containing material 515 may be characterized by a germanium concentration of about 35 at.% or less, and can be characterized by germanium concentrations of about 32.5 at.% or less, about 30 at.% or less, about 27.5 at.% or less, about 25 at.% or less, about 22.5 at.% or less, about 20 at.% or less, about 17.5 at.% or less, about 15 at.% or less, or lower. Conversely, the material 530 containing the second silicon and germanium may be characterized by a germanium concentration of about 35 at.% or more, and may be characterized by germanium concentrations of about 37.5 at.% or more, about 40 at.% or more, about 42.5 at.% or more, about 45 at.% or more, about 47.5 at.% or more, about 50 at.% or more, about 52.5 at.% or more, about 55 at.% or more, about 55 at.% or more, about 60 at.% or more, or higher. Furthermore, the material 530 containing the second silicon and germanium may be a doped material. In embodiments, the material 530 containing the second silicon and germanium may be doped with boron, for example.

[0069]

[0074] Figure 5B may show a structure after some operations of the method according to the present technology have been performed, as described with respect to Figure 4 above. When the substrate is brought into contact with the oxygen-containing precursor, such as in step 430 of method 400, at least a portion of the second layer of the silicon-germanium-containing material may be oxidized. A portion of the second layer 535 of the silicon-germanium-containing material may be the oxidized silicon-germanium-containing material. A portion of the second layer 535 of the silicon-germanium-containing material may come into contact with the oxygen-containing material 520 and / or the spacer material 525. As described with respect to Figure 4 above, and as previously stated with respect to the method according to the present technology, the second layer 530 of the silicon-germanium-containing material may be selectively oxidized with respect to the first layer 515 of the silicon-germanium-containing material because the germanium concentration in the second layer 530 of the silicon-germanium-containing material increases. The spacer material 525 may be porous. Therefore, during subsequent etching to remove the first silicon-germanium material 515, etchant species may penetrate the spacer material 525 and reach the second layer 530 of the silicon-germanium material. If a portion of the second layer 535 of the silicon-germanium material does not block the etchant species, a portion of the second layer 530 of the silicon-germanium material may be etched.

[0070]

[0075] Figure 5C shows the structure after further operations of the method according to the present technique have been performed, as described with respect to Figure 4 above. Etching may be performed to remove the silicon-germanium-containing material 515. Etching may remove the first silicon-germanium-containing material 515 to form nanowires / nanosheets of silicon-containing material 510 useful for GAA applications. The structure 500 may show minimal or zero etching of the second layer 530 of the silicon-germanium-containing material by selective oxidation of a portion of the second layer 535 of the silicon-germanium-containing material.

[0071]

[0076] Figure 5D shows the structure after further operations of the method according to the present technique have been performed, as described with respect to Figure 4 above. Etching may be performed to remove a portion of the silicon-containing material 510. Etching may remove a portion of the silicon-containing material 510 to reduce and / or remove germanium residue from the nanowires / nanosheets of the previously removed first silicon and germanium-containing material 515. The smallest portion of the silicon-containing material 510 may be removed to reduce germanium residue while retaining as much of the silicon-containing material 510 as possible.

[0072]

[0077] The above description provides numerous details for illustrative purposes to facilitate understanding of various embodiments of this technology. However, it will be obvious to those skilled in the art that certain embodiments can be practiced without some of these details, or with additional details.

[0073]

[0078] While several embodiments have been disclosed, those skilled in the art will recognize that various modifications, alternative structures, and equivalents can be used without departing from the spirit of the embodiments. Furthermore, some well-known processes and elements have not been described to avoid unnecessarily obscuring the Art. Accordingly, the descriptions in the prior specification should not be construed as limiting the scope of the Art. Moreover, while methods or processes may be described sequentially or stepwise, it should be understood that steps may be performed simultaneously or in an order different from that listed.

[0074]

[0079] Where a range of values ​​is provided, unless explicitly stated otherwise in the context, each intervening value between the upper and lower limits of that range is, of course, specifically disclosed down to the smallest unit of the lower limit. Any narrow range between any listed value or any unlisted intervening value within the listed range, and any other listed or intervening value within that listed range are also included. The upper and lower limits of such narrower ranges may be individually included in or excluded from that range. Each range in which one, neither, or both of the limit values ​​are included is also included in the Art, provided that there are limit values ​​specifically excluded within the listed range. Where a defined range includes one or both of the limit values, the range excluding one or both of the included limit values ​​is also included.

[0075]

[0080] As used herein and in the claims, the singular forms “a,” “an,” and “the” include multiple references unless the context clearly indicates otherwise. Thus, for example, a reference to “precursor” includes a reference to multiple such precursors, and a reference to “material” includes one or more materials, as well as their equivalents known to those skilled in the art, and so on.

[0076]

[0081] Furthermore, the terms “comprise(s),” “comprising,” “contain(s),” “containing,” “include(s),” and “including,” as used herein and in the claims, are intended to identify the presence of the described features, integers, components, or steps, but not to exclude the presence or addition of one or more other features, integers, components, processes, operations, or groups.

Claims

1. A semiconductor processing method, The present invention provides an oxygen-containing precursor to a processing area of ​​a semiconductor processing chamber, wherein a substrate is housed within the processing area, and a first layer of a material containing silicon and germanium, a second layer of a material containing silicon and germanium, and a layer of a silicon-containing material are arranged on the substrate. The process involves bringing the substrate into contact with the oxygen-containing precursor, wherein the contact oxidizes at least a portion of the second layer of the material containing silicon and germanium, To provide the first etchant precursor to the processing region, The process involves bringing the substrate into contact with the first etchant precursor, wherein the contact selectively etches the first layer of the silicon and germanium-containing material, To provide a second etchant precursor to the aforementioned processing region, The process involves bringing the substrate into contact with the second etchant precursor, wherein the contact etches a portion of the silicon-containing material layer, and the process involves bringing the substrate into contact with the precursor. A semiconductor processing method, including the following.

2. The first layer of the material containing silicon and germanium is characterized by a first germanium concentration. The second layer of the material containing silicon and germanium is characterized by a second germanium concentration. The first germanium concentration is lower than the second germanium concentration. The semiconductor processing method according to claim 1.

3. The oxygen-containing precursor is diatomic oxygen (O ２ ) or steam (H ２ The semiconductor processing method according to claim 1, comprising O).

4. The semiconductor processing method according to claim 1, further comprising forming a plasma ejecta of the oxygen-containing precursor.

5. The semiconductor processing method according to claim 1, wherein the second etchant precursor includes a fluorine-containing precursor.

6. The semiconductor processing method according to claim 1, further comprising providing a hydrogen-containing precursor together with the second etchant precursor.

7. The semiconductor processing method according to claim 1, wherein a portion of the layer of the silicon-containing material is characterized by a thickness of about 7 nm or less.

8. The semiconductor processing method according to claim 1, wherein the pressure in the processing area is maintained at approximately 30 Torr or less.

9. The semiconductor processing method according to claim 1, wherein contact with the first etchant precursor etches the first layer of the silicon and germanium-containing material with a selectivity of about 40:1 or more for the second layer of the silicon and germanium-containing material.

10. The semiconductor processing method according to claim 1, wherein the temperature within the processing area is maintained at approximately 150°C or higher.

11. The semiconductor processing method according to claim 1, wherein contacting the substrate with the oxygen-containing precursor, contacting the substrate with the first etchant precursor, and contacting the substrate with the second etchant precursor are performed on a single mainframe.

12. A semiconductor processing method, The present invention provides an oxygen-containing precursor to a processing area of ​​a semiconductor processing chamber, wherein a substrate is housed within the processing area, and a first layer of a material containing silicon and germanium, a second layer of a material containing silicon and germanium, and a layer of a silicon-containing material are arranged on the substrate, and the first layer of the material containing silicon and germanium is characterized by a lower germanium concentration than that of the second layer of the material containing silicon and germanium. The process involves bringing the substrate into contact with the oxygen-containing precursor, wherein the contact oxidizes at least a portion of the second layer of the material containing silicon and germanium, To provide a first fluorine-containing precursor to the processing region, The substrate is brought into contact with the first fluorine-containing precursor, wherein the contact etches the first layer of the silicon-germanium-containing material with respect to the second layer of the silicon-germanium-containing material with a selectivity of approximately 40:1 or more, To provide a second fluorine-containing precursor to the aforementioned processing region, Forming plasma emissions of the second fluorine-containing precursor, The substrate is brought into contact with the second fluorine-containing precursor, wherein the contact etches the silicon-containing material layer between approximately 2 nm and approximately 5 nm, and the substrate is brought into contact with the precursor. A semiconductor processing method, including the following.

13. The semiconductor processing method according to claim 12, wherein the first layer of the material containing silicon and germanium is characterized by a germanium concentration of about 35 at.% or less.

14. The semiconductor processing method according to claim 12, wherein the second layer of the silicon and germanium-containing material comprises a doped silicon and germanium-containing material.

15. The oxygen-containing precursor is diatomic oxygen (O ２ ) or steam (H ２ The semiconductor processing method according to claim 12, including O).

16. H ２ The semiconductor processing method according to claim 15, further comprising forming a plasma emission of O.

17. The semiconductor processing method according to claim 12, wherein, after contacting the substrate with the second fluorine-containing precursor, the surface of the silicon-containing material layer is characterized by a germanium concentration of about 1.5 at.% or less.

18. A semiconductor processing method, The oxygen-containing precursor is provided to the processing area of ​​a semiconductor processing chamber, wherein the oxygen-containing precursor is diatomic oxygen (O ２ ) or steam (H ２ To provide an oxygen-containing precursor comprising O), wherein a substrate is housed within the processing region, and a first layer of a material containing silicon and germanium, a second layer of a material containing silicon and germanium, and a layer of a silicon-containing material are arranged on the substrate, and the first layer of the material containing silicon and germanium is characterized by a lower germanium concentration than that of the second layer of the material containing silicon and germanium, The process involves bringing the substrate into contact with the oxygen-containing precursor, wherein the contact oxidizes at least a portion of the second layer of the material containing silicon and germanium, To provide a first fluorine-containing precursor to the processing region, The substrate is brought into contact with the first fluorine-containing precursor, wherein the contact selectively etches the first layer of the silicon and germanium-containing material, To provide a second fluorine-containing precursor and a hydrogen-containing precursor in the aforementioned processing region, Forming plasma emissions of the second fluorine-containing precursor and the hydrogen-containing precursor, The process involves bringing the substrate into contact with the plasma emitted from the second fluorine-containing precursor and the hydrogen-containing precursor, wherein the contact etches the silicon-containing material layer between approximately 2 nm and approximately 5 nm, and the substrate is brought into contact with the substrate. A semiconductor processing method, including the following.

19. The semiconductor processing method according to claim 18, wherein the temperature within the processing area is maintained at approximately 200°C or higher.

20. The semiconductor processing method according to claim 18, wherein, after contacting the substrate with the second fluorine-containing precursor, the surface of the silicon-containing material layer is characterized by a germanium concentration of about 1.0 at.% or less.

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