Methods for forming a semiconductor structure and related semiconductor structures
A method for forming a forming a semiconductor structure is disclosed. The method may include: forming a silicon oxide layer on a surface of a substrate, depositing a silicon germanium (Si 1-x Ge x ) seed layer directly on the silicon oxide layer, and depositing a germanium (Ge) layer directly on the silicon germanium (Si 1-x Ge x ) seed layer. Semiconductor structures including a germanium (Ge) layer deposited on silicon oxide utilizing an intermediate silicon germanium (Si 1-x Ge x ) seed layer are also disclosed.
1. A method for forming a semiconductor structure, the method comprising:
forming a silicon oxide layer on a surface of a substrate; using a chemical vapor deposition process, depositing a silicon germanium (Si1-xGex) seed layer, where x is between 0.01 and 0.3, at a temperature between about 250° C. and about 500° C. directly on the silicon oxide layer; and depositing a germanium (Ge) layer directly on the silicon germanium (Si1-xGex) seed layer, wherein the germanium layer has a thickness of between 5 nanometers to 15 nanometers, wherein the silicon germanium (Si1-xGex) seed layer has a thickness of less than 30 nm, wherein depositing the silicon germanium (Si1-xGex) seed layer comprises flowing trisilane (Si3H8), tetrasilane (Si4H8), isopentasilane (Si5H12), or neopentasilane (Si5H12) as a silicon precursor, and wherein the silicon germanium (Si1-xGex) seed layer is amorphous, and wherein depositing the silicon germanium (Si1-xGex) seed layer further comprises, depositing the silicon germanium (Si1-xGex) seed at a reaction chamber pressure of between approximately 10 Torr and approximately 760 Torr.
2. The method of claim 1 , wherein x is less than 0.2.
3. The method of claim 1 , wherein depositing the silicon germanium (Si1-xGex) seed layer further comprises flowing germane (GeH4) as a germanium precursor.
4. The method of claim 1 , wherein depositing the silicon germanium (Si1-xGex) seed layer further comprises flowing trisilane (Si3H8) as a silicon precursor.
5. The method of claim 1 , wherein the silicon germanium (Si1-xGex) seed layer has a thickness of between 1 nanometer to 10 nanometers.
6. The method of claim 1 , wherein the germanium (Ge) layer has an amorphous crystalline structure.
7. The method of claim 1 , wherein depositing the germanium layer occurs at a substrate temperature of between approximately 300° C. and approximately 350° C.
8. The method of claim 1 , wherein depositing the germanium layer further comprises flowing germane (GeH4) as a germanium precursor.
9. The method of claim 1 , wherein the germanium layer has a polycrystalline crystalline structure.
10. The method of claim 1 , wherein the germanium layer has a substantially monocrystalline crystalline structure.
11. The method of claim 1 , wherein the germanium layer has a carrier mobility of greater than 30 cm2/(Vs).
12. The method of claim 1 , further comprising heating the germanium layer to a temperature greater than 400° C. to recrystallize the germanium layer.
13. The method of claim 1 , wherein the germanium layer comprises a channel region of a semiconductor device structure.
14. The method of claim 1 , further comprising depositing an additional silicon dioxide layer directly on the germanium layer.
15. The method of claim 1 , wherein depositing the silicon germanium (Si1-xGex) seed layer further comprises flowing germane (GeH4), digermane (Ge 2 H 6 ), or germanylsilane (GeH 6 Si) as a germanium precursor.
16. The method of claim 1 , wherein the germanium precursor comprise a Si—Ge-hydride precursor.
17. The method of claim 16 , wherein the Si—Ge-hydride precursor comprises (H 3 Ge) x SiH 4-x , wherein x=1 to 4 or (H 2 Si) x , Ge 4-x , wherein x=1 to 4.