A method for forming silicon compounds within a high aspect ratio structure using a hybrid process.
A hybrid deposition process with controlled temperature and pressure cycles addresses non-uniformity in silicon compound deposition in 3D DRAM devices, improving electrical properties consistency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-03-26
- Publication Date
- 2026-04-14
AI Technical Summary
Conventional deposition techniques for forming silicon compounds in 3D DRAM devices result in non-uniformity due to concentration gradients within high aspect ratio features, leading to variations in electrical properties.
A hybrid deposition process involving multiple cycles of precursor gas supply and purge gas application at varying temperatures and pressures to control the deposition of silicon compounds within high aspect ratio structures.
The method ensures uniform deposition of silicon compounds, enhancing the electrical properties consistency of 3D DRAM devices by minimizing variations.
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Abstract
Description
Technical Field
[0001] The embodiments described herein generally relate to the manufacture of semiconductor devices, and more particularly, to systems and methods for forming bit lines in three-dimensional dynamic random access memory devices.
Background Art
[0002] Three-dimensional (3D) dynamic random access memory (DRAM) devices pose challenges to manufacturability due to their 3D design and small size. Each individual memory cell, which includes a field effect transistor (FET) device, needs to be connected to a bit line at the source / drain region of the FET device. The manufacture of such bit lines typically requires a plurality of process steps, including a via line process and a high aspect ratio (HAR) etching process for forming slots for the bit lines. For example, a 3D DRAM device may include alternating layers of silicon-based layers (P), oxides (O), and nitrides (N). In some configurations of the 3D DRAM structure, the silicon-based layers are selectively recessed, while in some other configurations, the silicon-based layers are exposed at the vertical bit line openings. In 3D memory structures such as 3D DRAM, it is necessary to form silicon compound contacts on the exposed portions of the silicon-based layers formed on the sidewalls of deep HAR holes or deep HAR trenches. Conventional deposition techniques typically form a silicon compound layer under one specific optimized deposition condition, but the concentration gradient of the nuclei occurring during transport within the deep holes / trenches essentially causes non-uniformity in the deposition. This conventional approach for forming a silicon compound layer within the vertical bit line features results in variations in the properties of the silicon compound layer, which in turn leads to variations in the electrical properties of 3D DRAM devices.
[0003] Therefore, there is a need for a system and method that can manufacture vertical bit lines within a 3D DRAM device to solve the problems described herein.
Summary of the Invention
[0004] This disclosure generally provides a method for fabricating silicon compounds within high-aspect-ratio structures by a hybrid process. The method comprises depositing layers within high-aspect-ratio features formed within a device layer stack. The device layer stack comprises a repeating stack of ONPN layers. The method comprises supplying a first precursor gas to the surface of a substrate placed within a processing area of a process chamber, the processing area being maintained at a first processing pressure while the substrate is maintained at a first temperature for a first period. A purge gas is supplied to the processing area for a second period, and the purge gas is supplied after the first period has elapsed. A second precursor gas is supplied to the surface of a substrate placed within a processing area of a process chamber, the second processing area being maintained at a second processing pressure while the substrate is maintained at a second temperature for a third period. A purge gas is supplied to the processing area for a fourth period, and the purge gas is supplied after the third period has elapsed.
[0005] The disclosure also includes a method in which a first precursor gas is supplied over a first period, and a purge gas is supplied to the processing area over a second period, which is repeated two or more times periodically before a second precursor gas is supplied to the surface of the substrate over a third period. The disclosure also includes a method in which, after supplying the first precursor gas to the surface of the substrate over a first period, a second precursor gas is supplied over a third period two or more times, and a purge gas is supplied to the processing area over a fourth period, before the first precursor gas is supplied to the surface of the substrate over a first period a second time.
[0006] This disclosure also generally provides a method for fabricating silicon compounds within high-aspect-ratio structures by a hybrid process. The method involves depositing layers within high-aspect-ratio features formed within a device layer stack. The device layer stack comprises a repeating stack of ONPN layers. The method includes supplying a first precursor gas to the surface of a substrate placed within a processing area of a process chamber, the processing area being maintained at a first processing pressure while the substrate is maintained at a first temperature for a first period. A purge gas is supplied to the processing area for a second period, and the purge gas is supplied after the first period has elapsed. The first precursor gas is supplied to the surface of the substrate, and the processing area is maintained at a second processing pressure while the substrate is maintained at a second temperature for a third period. A purge gas is supplied to the processing area for a fourth period, and the purge gas is supplied after the third period has elapsed. A second precursor gas is supplied to the surface of a substrate placed within the processing area of the process chamber, and the second processing area is maintained at a third processing pressure while the substrate is maintained at a third temperature for a fifth period. A purge gas is supplied to the processing area for a sixth period, and the purge gas is supplied after the fifth period has elapsed.
[0007] This disclosure also generally provides a method for fabricating silicon compounds within high-aspect-ratio structures by a hybrid process. The method involves depositing layers within high-aspect-ratio features formed within a device layer stack. The device layer stack comprises a repeating stack of ONPN layers. The method includes supplying a first precursor gas to the surface of a substrate placed within a processing area of a process chamber, the processing area being maintained at a first processing pressure while the substrate is maintained at a first temperature for a first period. A purge gas is supplied to the processing area for a second period, and the purge gas is supplied after the first period has elapsed. A second precursor gas is supplied to the surface of the substrate, and the processing area is maintained at a second processing pressure while the substrate is maintained at a second temperature for a third period. A purge gas is supplied to the processing area for a fourth period, and the purge gas is supplied after the third period has elapsed. A second precursor gas is supplied to the surface of a substrate placed within the processing area of the process chamber, and the second processing area is maintained at a third processing pressure while the substrate is maintained at a third temperature for a fifth period. A purge gas is supplied to the processing area for a sixth period, and the purge gas is supplied after the fifth period has elapsed.
[0008] To enable a more detailed understanding of the above-mentioned features of this disclosure, a more specific description of this disclosure, which has been briefly summarized above, can be obtained by referring to embodiments, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings show only exemplary embodiments and should not be considered limiting in scope, as other equally valid embodiments may be recognized. [Brief explanation of the drawing]
[0009] [Figure 1A] This figure shows a substrate undergoing a selective deposition process according to an embodiment of the present disclosure. Figure 1A shows the substrate before performing the selective deposition process. [Figure 1B]This figure shows a substrate undergoing a selective deposition process according to an embodiment of the present disclosure. Figure 1B shows a substrate during or after a cleaning process. [Figure 1C] This figure shows a substrate undergoing a selective deposition process according to an embodiment of the present disclosure. Figure 1C shows a substrate undergoing the selective deposition process. [Figure 2] This figure shows a first iterative selective deposition process according to an embodiment of the present disclosure. [Figure 3] This figure shows a second iterative selective deposition process according to an embodiment of the present disclosure. [Figure 4] This figure shows a third iterative selective deposition process according to an embodiment of the present disclosure. [Figure 5] This figure shows a fourth iterative selective deposition process according to an embodiment of the present disclosure. [Figure 6] This figure shows a fifth iterative selective deposition process according to an embodiment of the present disclosure. [Figure 7] This figure shows a sixth iterative selective deposition process according to an embodiment of the present disclosure. [Figure 8] This figure shows a seventh iterative selective deposition process according to an embodiment of the present disclosure. [Figure 9] This figure shows an eighth iterative selective deposition process according to an embodiment of the present disclosure. [Figure 10] This figure shows a ninth iterative selective deposition process according to an embodiment of the present disclosure. [Figure 11] This figure shows a tenth iterative selective deposition process according to an embodiment of the present disclosure. [Figure 12] This figure shows an eleventh iterative selective deposition process according to an embodiment of the present disclosure. [Figure 13] This figure shows a twelfth iterative selective deposition process according to an embodiment of the present disclosure. [Figure 15] This figure shows a thirteenth iterative selective deposition process according to an embodiment of the present disclosure. [Figure 16] This figure shows a 14th iterative selective deposition process according to an embodiment of the present disclosure. [Figure 17] FIG. 15 is a diagram showing a 15th iterative selective deposition process according to an embodiment of the present disclosure. [Figure 18] FIG. 5 is a diagram showing an example of a processing sequence including two process steps according to an embodiment of the present disclosure. [Figure 19] FIG. 8 is a diagram showing three process steps including a first selective deposition process, a second selective deposition process, and a third selective deposition process according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION
[0010] For ease of understanding, where possible, the same reference numerals are used to denote the same elements common to the drawings. It is contemplated that elements and features of one embodiment may be beneficially incorporated into other embodiments without further elaboration.
[0011] The present disclosure relates to a method of selectively forming a silicon compound within a high aspect ratio structure by using a multi-step deposition process, often referred to herein as a hybrid deposition process.
[0012] The method includes receiving a wafer having a plurality of natural oxide layers covering a silicon-based layer of a 3D DRAM structure, as shown in FIG. 1A. The wafer includes a plurality of vertical trenches extending from the top surface to the bottom surface of the wafer. The vertical trenches include an oxide layer (e.g., SiO x ), a first nitride layer (e.g., silicon nitride (Si x N y )), a silicon layer (e.g., polysilicon, a-silicon, c-silicon), and a second nitride layer (e.g., silicon nitride (Si x N yIt is formed within a stack of repeating ONPN layers that includes a sequential repeat stack of (( )). The groove can have a depth of from about 2 μm to about 6 μm, such as, for example, about 2 μm, about 3 μm, about 4 μm, about 5 μm, about 6 μm, etc. The groove can include an aspect ratio of from about 1:8 to about 1:160, such as, for example, about 1:8, about 1:10, about 1:50, about 1:100, about 1:150, about 1:160, etc.
[0013] As shown in FIG. 1B, the method includes cleaning the wafer by either wet etching, such as a d-HF solution, or dry etching (NH3-HF) to remove the native oxide formed on the silicon-containing layer.
[0014] As shown in FIG. 1C, the method includes performing a first selective deposition process. The deposition process is performed within the processing region of the deposition chamber. The first selective deposition process includes dosing a cleaned wafer with a precursor gas that includes a metal nuclide, such as molybdenum chloride, titanium chloride, etc., as shown in FIG. 1C. The metal nuclide may include molybdenum pentachloride. The metal nuclide may include titanium pentachloride. The dose is applied for less than about 3 seconds. For example, without limitation, the dose may be applied for less than 2 seconds. As a further non-limiting example, the dose may be applied over a period of from about 2 seconds to about 3 seconds, such as, for example, about 2.1 seconds, about 2.2 seconds, about 2.3 seconds, about 2.4 seconds, about 2.5 seconds, about 2.6 seconds, about 2.7 seconds, about 2.8 seconds, about 2.9 seconds, about 3.0 seconds, etc.
[0015] Next, a purge gas (such as an inert gas) is provided to the wafer disposed within the deposition chamber to remove one or more of the chlorinated nuclides. The purge gas is an inert gas capable of removing the chlorinated nuclides, such as argon, nitrogen, helium, etc. The purge gas is applied for a time period from about 1 times the dose time to about 4 times the dose time. For example, if the dose time is about 3 seconds, the purge time may be about 4.5 seconds. As a further non-limiting example, if the dose time is about 3.5 seconds, the purge time may be about 1.5 seconds.
[0016] The first selective deposition process involves a first temperature. While we do not wish to be bound by theory, the temperature of the wafer during processing can affect the location of the deposition process within the vertical grooves formed in the multilayer stack. For example, high temperatures above approximately 380°C may improve the efficiency of depositing metallic nuclides toward the upper section of the vertical groove, while low temperatures below approximately 350°C may improve the efficiency of depositing metallic nuclides toward the lower section of the vertical groove. The first temperature is high, and the first temperature is higher than approximately 380°C.
[0017] The first selective deposition process involves a first pressure. While we do not wish to be bound by theory, the pressure in the chamber may influence the location of the deposition process within the vertical trench. For example, pressures above approximately 10 Torr may improve the efficiency of depositing metallic nuclides, such as molybdenum chloride, titanium chloride, or combinations thereof, towards the top of the vertical trench, while low pressures below approximately 10 Torr may improve the efficiency of depositing metallic nuclides towards the bottom of the vertical trench. The first pressure is high, and the first pressure is approximately 10 Torr to approximately 760 Torr, for example, approximately 10 Torr to approximately 700 Torr, approximately 10 Torr to approximately 500 Torr, approximately 10 Torr to approximately 300 Torr, or approximately 10 Torr to approximately 100 Torr.
[0018] The method includes performing a second selective deposition process, as shown in Figures 2 to 17. The second selective deposition process includes dosing a precursor gas containing a metallic nuclide, such as molybdenum chloride, titanium chloride, or a combination thereof, onto a cleaned wafer, as described herein. A purge gas is applied to remove the chlorinated nuclide from the wafer, as described above. For example, the second selective deposition process may include a dosing time of about 3 seconds and a purge time of about 7 seconds.
[0019] The second selective deposition process includes a second temperature. In some embodiments, the second temperature is low, and is between approximately 300°C and approximately 350°C, for example, approximately 300°C to approximately 350°C, approximately 310°C to approximately 350°C, or approximately 335°C to approximately 350°C. The second selective deposition process includes a second pressure. In some embodiments, the second pressure is low, and is between approximately 0.001 Torr and approximately 10 Torr, for example, approximately 0.001 Torr to approximately 8 Torr, approximately 0.01 Torr to approximately 5 Torr, approximately 0.1 Torr to approximately 3 Torr, or approximately 0.5 Torr to approximately 1 Torr.
[0020] The method may include performing a third selective deposition process, as shown in Figures 2 to 17. The third selective deposition process includes dosing a cleaned wafer with a metallic nuclide, such as molybdenum chloride, titanium chloride, or a combination thereof, as described herein. As described above, a purge gas is applied to remove the chlorinated nuclide from the wafer.
[0021] The third selective deposition process includes a third temperature. The third temperature is a moderate temperature, and is approximately 350°C to 380°C, for example, approximately 350°C to 370°C, approximately 355°C to 370°C, or approximately 360°C to 370°C. The third selective deposition process also includes a third pressure. The third pressure is a moderate pressure, and is approximately 10 Torr to 400 Torr, for example, approximately 10 Torr to 400 Torr, approximately 12 Torr to 300 Torr, approximately 14 Torr to 200 Torr, or approximately 14 Torr to 100 Torr.
[0022] In one embodiment, the method includes an iterative process that repeats one or more of the first selective deposition process and the second selective deposition process, as shown in Figures 2 to 7. For example, but not limited to, the iterative process may include performing the first selective deposition process, the second selective deposition process, and repeating the first selective deposition process. As a further non-limiting example, the iterative process may include performing the first selective deposition process, the second selective deposition process, and repeating the second selective deposition process. As a further non-limiting example, the iterative process may include performing the first selective deposition process, the second selective deposition process, and repeating the first and second selective deposition processes at least one more time. As a further non-limiting example, the iterative process may include performing the first selective deposition process, repeating the first selective deposition process, and performing the second selective deposition process.
[0023] In one embodiment, the method includes an iterative process that repeats one or more of a first selective deposition process, a second selective deposition process, or a third selective deposition process, as shown in Figures 5 to 6. For example, but not limited to, the iterative process may include performing the first selective deposition process, the second selective deposition process, and the third selective deposition process, and repeating the first selective deposition process. As a further non-limiting example, the iterative process may include performing the first selective deposition process, the second selective deposition process, and the third selective deposition process, and repeating the second selective deposition process. As a further non-limiting example, the iterative process may include performing the first selective deposition process, the second selective deposition process, and the third selective deposition process, and repeating the third selective deposition process.
[0024] The iteration may be performed after the first selective deposition process, the second selective deposition process, and the third selective deposition process, or between each process, as shown in Figures 8 to 15. For example, but not limited to, the iterative process may include performing the first selective deposition process, repeating the first selective deposition process, and performing the third selective deposition process following the second selective deposition process. As a further non-limiting example, the iterative process may include performing the first and second selective deposition processes, repeating the first selective deposition process, and performing the third selective deposition process. As a further non-limiting example, the iterative process may include performing the first and second selective deposition processes, repeating the second selective deposition process, and performing the third selective deposition process. As a further non-limiting example, the iterative process may include performing the first, second, and third selective deposition processes, and repeating the first selective deposition process. As a further non-limiting example, the iterative process may include performing a first selective deposition process, a second selective deposition process, and a third selective deposition process, and repeating the second selective deposition process.
[0025] In some embodiments, one or more process variables may differ from process variables in other process sequences. For example, the first selective deposition process (A) involves dosing a first metallic nuclide, e.g., molybdenum chloride, titanium chloride, or a combination thereof, at a pressure of approximately 10 Torr to approximately 760 Torr, e.g., approximately 10 Torr to approximately 700 Torr, approximately 10 Torr to approximately 500 Torr, approximately 10 Torr to approximately 300 Torr, or approximately 10 Torr to approximately 100 Torr, and a temperature of approximately 360°C to approximately 400°C, e.g., approximately 360°C to approximately 390°C, approximately 370°C to approximately 390°C, or approximately 375°C to approximately 395°C, and purging the metallic nuclide with an inert gas using a purge time of approximately 0.1 sec to approximately 2 sec, e.g., approximately 0.1 sec to approximately 1.9 sec, approximately 0.5 sec to approximately 1.8 sec, or approximately 1 sec to approximately 1.5 sec, and approximately 0.001 Torr to approximately 50 This may include performing a second deposition process (B) by dosing a second metallic nuclide, e.g., molybdenum chloride, titanium chloride, or a combination thereof, at a pressure of Torr, for example, 0.001 Torr to about 48 Torr, about 0.01 Torr to about 45 Torr, about 0.1 Torr to about 33 Torr, or about 0.5 Torr to about 20 Torr, and a temperature of about 300°C to about 350°C, for example, about 300°C to about 350°C, about 310°C to about 350°C, or about 335°C to about 350°C, and purging the second metallic nuclide with an inert gas using a purge time of about 2.1 seconds to about 30 seconds, for example, about 2.1 seconds to about 28 seconds, about 3 seconds to about 25 seconds, about 4 seconds to about 20 seconds, or about 5 seconds to about 15 seconds. In one embodiment, the third selective deposition process (C) may include parameters similar to those of A, and / or the third selective deposition process may include process parameters different from either A or B.
[0026] Figure 16 shows an example of a processing sequence comprising two process steps, in which one or more first selective deposition processes (P1) and one or more second selective deposition processes (P2) can be individually repeated 0 to N times, where N is an integer greater than 0 (e.g., 1, 2, 5, 10, 100, etc.), or interleaved in any desired sequence to form a deposition layer within a feature. Each selective deposition process in the process sequence includes at least one process variable that is different from the process variables in the other process sequences. In one example, the process variables are selected from processing pressure, temperature, deposition time, and the ratio of deposition time to purge time. In one example, the processing sequence may include the sequence P1-P2-P1-P2...P1-P2. In some embodiments, each selective deposition process (e.g., P1 or P2) may be executed two or more times periodically before another selective deposition process is executed. In one example, the processing sequence may include the sequence P1-P1-P2-P1-P1-P2. In yet another example, the processing sequence could include the sequence P1-P2-P2-P1-P2...P1-P2-P2-P1-P2.
[0027] Figure 17 shows an example of a processing sequence comprising three process steps, in which one or more first selective deposition processes (P1), one or more second selective deposition processes (P2), and one or more third selective deposition processes (P3) are each repeated individually 0 to N times, where N is an integer greater than 0 (e.g., 1, 2, 5, 10, 100, etc.), or interleaved in any desired sequence, to form a deposited layer within the feature. In one example, the processing sequence may include the sequence P1-P2-P3-P1-P2-P3...P1-P2-P3.
[0028] Figure 18 shows an example of a processing sequence comprising two process steps, in which one or more first selective deposition processes (A) and one or more second selective deposition processes (B) can be individually repeated 0 to N times, where N is an integer greater than 0 (e.g., 1, 2, 5, 10, 100, etc.), or interleaved in any desired sequence to form a deposition layer within a feature. Each of the selective deposition processes in the process sequence includes at least one process variable that is different from the process variables in the other process sequences. In one example, the process variables are selected from processing pressure, temperature, deposition time, and the ratio of deposition time to purge time. In one example, the processing sequence may include the sequence BA-BA-BA…BA. In another example, the processing sequence may include the sequence BBA-BBA…BBA. In yet another example, the processing sequence may include a third selective deposition process (C), and the processing sequence may include the sequence BAC-BAC-BAC…BAC.
[0029] Figure 19 shows a three-process step sequence including a first selective deposition process (P1) for depositing a first metallic nuclide, such as molybdenum chloride, titanium chloride, or a combination thereof. The first selective deposition process includes a first temperature (T1) of about 360°C to about 400°C, such as about 360°C to about 390°C, about 370°C to about 390°C, or about 375°C to about 395°C, a first pressure of about 10 Torr to about 760 Torr, such as about 10 Torr to about 700 Torr, about 10 Torr to about 500 Torr, about 10 Torr to about 300 Torr, or about 10 Torr to about 20 Torr, and a temperature of about 360°C to about 400°C. The three-process step sequence includes a second selective deposition process (P2) for depositing a second metallic nuclide, such as molybdenum chloride, titanium chloride, or a combination thereof. The second selective deposition process includes a first temperature (T1) and a second pressure of about 1 Torr to about 6 Torr, e.g., about 1 Torr to about 5 Torr, about 2 Torr to about 4 Torr, or about 3 Torr to about 4 Torr. The third process step sequence includes a third selective deposition process (P3) for depositing a third metallic nuclide, e.g., molybdenum chloride, titanium chloride, or a combination thereof, wherein the third metallic nuclide is the same as or different from the first or second metallic nuclide. The third selective deposition process includes a second temperature about 10°C to about 50°C higher than T1, e.g., about 370°C to about 450°C, e.g., about 370°C to about 440°C, about 380°C to about 420°C, or about 390°C to about 410°C. The third selective deposition process includes a third pressure of approximately 10 Torr to approximately 300 Torr, for example, approximately 10 Torr to approximately 280 Torr, approximately 10 Torr to approximately 200 Torr, approximately 10 Torr to approximately 100 Torr, or approximately 10 Torr to approximately 50 Torr. The three-process step sequence can then proceed to a first selective deposition process with a pressure of approximately 10 Torr to approximately 20 Torr and a temperature of approximately 360°C to approximately 400°C, and the three-process step sequence can be repeated multiple times.
[0030] While the above applies to embodiments of the present disclosure, other embodiments and further embodiments of the present disclosure can be devised without departing from its basic scope, the scope of which is determined by the following claims.
Claims
1. A method for selectively depositing layers within a high aspect ratio feature formed in a device layer stack, wherein the device layer stack includes a repeating stack of ONPN layers. Supplying a first precursor gas to the surface of a substrate placed within a processing area of a process chamber, wherein supplying the first precursor gas includes maintaining the processing area at a first processing pressure while the substrate is maintained at a first temperature for a first period of time. Supplying purge gas to the processing area over a second period, wherein the supply of purge gas is provided after the first period has elapsed. Supplying a second precursor gas to the surface of the substrate disposed within the processing area of the process chamber, wherein supplying the second precursor gas includes maintaining the processing area at a second processing pressure while the substrate is maintained at a second temperature for a third period of time. Supplying the purge gas to the processing area over a fourth period, wherein the supply of the purge gas is provided after the third period has elapsed. Methods that include...
2. The method according to claim 1, wherein the first pressure is higher than the second pressure.
3. The method according to claim 2, wherein the first temperature is higher than the second temperature.
4. The method according to claim 1, wherein the second period is longer or shorter than the fourth period.
5. The method according to claim 1, wherein the first precursor gas and the second precursor gas each contain molybdenum or titanium.
6. The method according to claim 5, wherein the first precursor gas and the second precursor gas contain titanium chloride.
7. The method according to claim 5, wherein the first precursor gas and the second precursor gas contain molybdenum chloride.
8. The method according to claim 1, wherein the first ratio of the first period to the second period is greater than the second ratio of the third period to the fourth period.
9. The method according to claim 1, wherein the first ratio of the first period to the second period is smaller than the second ratio of the third period to the fourth period.
10. The method according to claim 1, wherein supplying the first precursor gas over the first period and supplying the purge gas to the processing area over the second period is periodically repeated two or more times before supplying the second precursor gas to the surface of the substrate over the third period.
11. The method according to claim 1, wherein the P layer in the ONPN stack is a silicon-containing layer.
12. The method according to claim 11, wherein the O layer and the N layer in the ONPN stack are an oxide layer and a nitride layer, respectively.
13. A method for selectively depositing layers within a high aspect ratio feature formed in a device layer stack, wherein the device layer stack includes a repeating stack of ONPN layers. Supplying a first precursor gas to the surface of a substrate placed within a processing area of a process chamber, wherein supplying the first precursor gas includes maintaining the processing area at a first processing pressure while the substrate is maintained at a first temperature for a first period of time. Supplying purge gas to the processing area over a second period, wherein the supply of purge gas is provided after the first period has elapsed. Supplying the first precursor gas to the surface of the substrate, wherein supplying the first precursor gas includes maintaining the processing area at a second processing pressure while the substrate is maintained at a second temperature for a third period of time, Supplying the purge gas to the processing area over a fourth period, wherein the supply of the purge gas is provided after the third period has elapsed. Supplying a second precursor gas to the surface of the substrate disposed within the processing area of the process chamber, wherein supplying the second precursor gas includes maintaining the processing area at a third processing pressure while the substrate is maintained at a third temperature for a fifth period of time. Supplying the purge gas to the processing area over a sixth period, wherein the supply of the purge gas is provided after the fifth period has elapsed. Methods that include...
14. The method according to claim 13, wherein the first pressure is the same as the second pressure.
15. The method according to claim 13, wherein the first temperature is the same as the second temperature.
16. The method according to claim 13, wherein the first pressure and the second pressure are different from the third pressure.
17. The method according to claim 13, wherein the first temperature and the second temperature are different from the third temperature.
18. The method according to claim 13, wherein the first precursor gas and the second precursor gas contain molybdenum or titanium.
19. The method according to claim 13, wherein the first precursor gas and the second precursor gas contain titanium chloride.
20. A method for selectively depositing layers within a high aspect ratio feature formed in a device layer stack, wherein the device layer stack includes a repeating stack of ONPN layers. Supplying a first precursor gas to the surface of a substrate placed within a processing area of a process chamber, wherein supplying the first precursor gas includes maintaining the processing area at a first processing pressure while the substrate is maintained at a first temperature for a first period of time. Supplying purge gas to the processing area over a second period, wherein the supply of purge gas is provided after the first period has elapsed. Supplying a second precursor gas to the surface of the substrate, wherein supplying the second precursor gas includes maintaining the processing area at a second processing pressure while the substrate is maintained at a second temperature for a third period of time. Supplying the purge gas to the processing area over a fourth period, wherein the supply of the purge gas is provided after the third period has elapsed. Supplying the second precursor gas to the surface of the substrate disposed in the processing area of the process chamber, wherein supplying the second precursor gas includes maintaining the processing area at a third processing pressure while the substrate is maintained at a third temperature for a fifth period of time. Supplying the purge gas to the processing area over a sixth period, wherein the supply of the purge gas is provided after the fifth period has elapsed. Methods that include...