Germanium semiconductor device and method of manufacturing the same
View Patent ↗A germanium semiconductor device and a method of manufacturing the same are provided. The method includes the steps of: forming an isolation layer on a substrate using a shallow trench; forming a silicon-nitride layer on the substrate, and selectively etching the silicon nitride layer to expose source and drain regions; injecting impurities onto a surface of the substrate over the exposed source and drain regions using delta-doping to form a delta-doping layer; selectively growing a silicon germanium layer containing impurities on the delta-doping layer; rapidly annealing the substrate and forming source and drain regions by diffusion of the impurities; depositing an insulating layer on the entire surface of the substrate; etching the insulating layer and forming source and drain contact parts to be in contact with source and drain terminals; depositing metal over the insulating layer having the source and drain contact parts thereon and forming a metal silicide layer; and after forming the silicide layer, forming the source and drain terminals to be in contact with the silicide layer. Accordingly, the source and drain regions having a shallow junction depth may be ensured by forming the source and drain regions through annealing after delta-doping and selectively growing the silicon germanium layer containing high-concentration impurities. Also, the germanium silicide layer is stably formed by the silicon germanium layer grown in the source and drain regions, and thus contact resistance is lowered and driving current of the device is improved.
1. A method of manufacturing a germanium semiconductor device, comprising the steps of:
forming an isolation layer on a Ge or GOI substrate using a shallow trench;
forming a silicon-nitride layer on the substrate, and selectively etching the silicon nitride layer to expose source and drain regions;
injecting impurities onto a surface of the substrate over the exposed source and drain regions using delta-doping to form a delta-doping layer;
selectively growing a silicon germanium layer containing impurities on the delta-doping layer;
rapidly annealing the substrate and forming source and drain regions by diffusion of the impurities;
depositing an insulating layer on the entire surface of the substrate;
etching the insulating layer and forming source and drain contact parts to be in contact with source and drain terminals;
depositing metal over the insulating layer having the source and drain contact parts thereon and forming a metal silicide layer; and
after forming the silicide layer, forming the source and drain terminals to be in contact with the metal silicide layer.
2. The method according to claim 1 , further comprising the steps of:
before forming the source and drain contact parts, forming a metal gate on the insulating layer, and forming an insulating passivation layer on the insulating layer having the metal gate thereon;
etching the insulating passivation layer and forming a gate contact part to expose the metal gate; and
forming a gate terminal electrically connected to the metal gate through the gate contact part.
3. The method according to claim 2 , wherein the source and drain contact parts are formed by etching the insulating layer and the insulating passivation layer.
4. The method according to claim 2 , wherein the gate terminal is formed together while forming the source and drain terminals.
5. The method according to claim 1 , further comprising the step of:
before forming the delta-doping layer and growing the silicon germanium layer,
cleaning the substrate.
6. The method according to claim 5 , wherein the substrate is cleaned using a diluted fluoric acid solution.
7. The method according to claim 1 , further comprising the step of:
before forming the delta-doping layer,
annealing the substrate in a chemical vapor deposition apparatus in a high-temperature H 2 gas atmosphere.
8. The method according to claim 7 , wherein the delta-doping layer is formed by injecting the impurities onto the surface of the source and drain regions using B 2 H 6 and PH 3 for 1 to 5 minutes.
9. The method according to claim 1 , wherein the silicon germanium layer is deposited using a mixture gas of SiH 2 Cl 2 /GeH 4 /HCl/H 2 or SiH 4 /GeH 4 /HCl/H 2 by a chemical vapor deposition method at a temperature of 550 to 700° C.
10. The method according to claim 9 , wherein the silicon germanium layer is deposited with a germanium content of 40 to 80% in the silicon germanium layer.
11. The method according to claim 9 , wherein the silicon germanium layer is deposited by injecting in-situ high-concentration impurities in the silicon-germanium layer.
12. The method according to claim 1 , wherein the source and drain regions are formed by high-temperature rapid thermal annealing at a temperature of 800 to 900° C.
13. The method according to claim 1 , wherein the step of forming silicide by depositing the metal comprises the steps of:
depositing nickel on the entire surface of the substrate; and
forming a nickel-germanium silicide layer on the silicon-germanium layer exposed through the source and drain contact parts by annealing.
14. The method according to claim 13 , wherein the annealing process is performed in a range from 500 to 600° C.
15. The method according to claim 1 , wherein the substrate is a germanium substrate or a germanium on insulator (GOI) substrate based on silicon.
16. The method according to claim 1 , wherein the insulating layer is a high-k metal oxide layer.
17. The method according to claim 1 , wherein the substrate is a germanium substrate or a GOI substrate based on a silicon substrate.
18. A germanium semiconductor device manufactured by the method according to claim 1 .