Method of forming an epitaxial layer
A method of forming a Si-comprising epitaxial layer selectively on a substrate and a semiconductor processing apparatus is disclosed. Embodiments of the presently described method of forming the Si-comprising epitaxial layer comprise performing a deposition process for forming the Si-comprising epitaxial layer selectively on a first exposed single crystalline surface relative to a second exposed single crystalline surface being different than the first exposed single crystalline surface.
1 . A method of forming a Si-comprising epitaxial layer selectively on a substrate, the method comprising:
providing the substrate to a process chamber, the substrate comprising an exposed surface, the exposed surface comprising a first exposed surface and a second exposed surface, and
performing a deposition process, thereby forming the Si-comprising epitaxial layer selectively on the first exposed surface, relative to the second exposed surface, the deposition process comprising providing, to the process chamber, a Si-containing precursor and a Ge-containing precursor,
wherein the Si-containing precursor is a halopolysilane precursor and wherein the first exposed surface is a single crystalline surface and wherein the second exposed surface is a single crystalline surface having a different crystal orientation than the first exposed surface, and
wherein the deposition process is a cyclic deposition process comprising one or more deposition cycles, wherein each deposition cycle further comprises providing an etching gas to the process chamber, thereby removing the Si-comprising epitaxial layer from the second exposed surface, and the cyclic deposition process is carried out until a desired thickness of the Si-comprising epitaxial layer is formed on the first exposed surface and where the second exposed surface is free of the Si-comprising epitaxial layer.
2 . The method according to claim 1 , wherein the halopolysilane precursor is SiH n X 3-n —(SiH 2 ) p —SiH m X 3-m , wherein n and m are independently selected from an integer having a value of at least 1 to at most 3, and wherein p is an integer from at least 1 to at most 3 and wherein X is a halogen.
3 . The method according to claim 2 , wherein p is equal to 1.
4 . The method according to claim 2 , wherein X is Cl.
5 . The method according to claim 1 , wherein the halopolysilane precursor is a chlorotrisilane.
6 . The method according to claim 1 , wherein the halopolysilane precursor is a 1-chlorotrisilane or a 1,3-dichlorotrisilane.
7 . The method according to claim 1 , wherein the first exposed surface consists of a Si {100} crystal facet and the second exposed surface consists of a higher order silicon crystal facet.
8 . The method according to claim 7 , wherein the higher order silicon crystal facet is a Si {110} crystal facet.
9 . The method according to claim 1 , wherein a temperature of the process chamber during the performing of the deposition process is less than 450° C.
10 . The method according to claim 1 , wherein the etching gas comprises Cl 2 gas and is being provided, into the process chamber, in the presence of a carrier gas, wherein flow of Cl 2 gas is in a range of 10 sccm to 100 sccm.
11 . The method according to claim 1 , wherein the process chamber is maintained at a pressure in a range of 10 Torr to 80 Torr during the performing of the deposition process.
12 . The method according to claim 1 , wherein the Si-containing precursor is provided to the process chamber at a flow in a range of 50 sccm to 1000 sccm.
13 . The method according to claim 1 , wherein the Si-containing precursor is provided, to the process chamber, during an overlapping period with a process gas comprising at least a dopant precursor, thereby forming a doped Si-comprising epitaxial layer.
14 . The method according to claim 13 , wherein the dopant precursor is phosphine and is provided to the process chamber at a flow in a range of 50 sccm to 900 sccm.
15 . The method according to claim 13 , wherein the Si-containing precursor is provided to the process chamber at a flow at about 1000 sccm.
16 . The method according to claim 13 , wherein the process gas further comprises the Ge-containing precursor, and wherein the dopant precursor is a p-type dopant precursor, thereby forming a p-doped SiGe epitaxial layer.
17 . The method according to claim 16 , wherein the Si-containing precursor is provided to the process chamber at a flow in a range of 200 sccm to 700 sccm and wherein a temperature of the process chamber during the performing of the deposition process is less than 400° C.
18 . The method according to claim 16 , wherein the Ge-containing precursor is GeH4 and wherein the p-type dopant precursor is B 2 H 6 .
19 . A substrate processing apparatus for forming the Si-comprising epitaxial layer selectively on the substrate, the apparatus comprising:
the process chamber constructed and arranged to hold the substrate,
a silicon precursor storage module comprising a halopolysilane precursor,
a germanium precursor storage module comprising a Ge-containing precursor,
a heater configured to heat and maintain a process temperature in the process chamber,
a pressure controller configured to attain and maintain process pressure in the process chamber, and
a controller operably connected to the silicon precursor storage module and to the germanium precursor storage module and configured to execute instructions stored in a non-transitory computer readable medium, and to cause the substrate processing apparatus to form the Si-comprising epitaxial layer on the first exposed surface of the substrate in accordance with a method according to claim 1 .