Deposition of germanium film
A method for forming a photodetector device includes forming waveguide feature on a substrate, and forming a photodetector feature including a germanium (Ge) film, the Ge film deposited on the waveguide feature using a plasma enhanced chemical vapor deposition (PECVD) process, the PECVD process having a deposition temperature from about 500° C. to about 550° C., and a deposition pressure from about 666.612 Pa to about 1066.579 Pa.
1. A method for forming a photodetector device, the method comprising:
forming a waveguide feature on a substrate; and
forming a photodetector feature including a germanium (Ge) film, the Ge film deposited on the waveguide feature using a plasma enhanced chemical vapor deposition (PECVD) process that reduces an incorporation of H in the germanium film and reduces a surface roughness of the germanium film, the PECVD process having a deposition temperature from 500° C. to 550° C., and a deposition power from 50 W to 200 W, wherein the PECVD process includes GeH 4 precursor diluted with He, wherein a ratio of the He to GeH 4 is about four parts He to one part GeH 4 .
2. The method of claim 1 , wherein the method further comprises:
forming an interfacial layer on the photodetector feature; and
forming vertical contacts and a metallization line.
3. The method of claim 1 , wherein the PECVD process has a deposition pressure from 666.612 Pa to 1066.579 Pa.
4. The method of claim 1 , wherein deposition temperature from 500° C. to 550° C. reduces a presence of Ge-H and (Ge-H 2 ) n in the Ge film.
5. The method of claim 1 , wherein the waveguide feature includes crystalline silicon.
6. The method of claim 2 , wherein the vertical contacts include a conductive material.
7. A method for forming a germanium film, the method comprising depositing a germanium film on a substrate using a plasma enhanced chemical vapor deposition (PECVD) process that reduces an incorporation of H in the germanium film and reduces a surface roughness of the germanium film, the PECVD process having a deposition temperature from 500° C. to 550° C., and a deposition power from 50 W to 200 W, wherein the PECVD process includes GeH 4 precursor diluted with He, wherein a ratio of the He to GeH 4 is about four parts He to one part GeH 4 .
8. The method of claim 7 , wherein the PECVD process has a deposition pressure from 666.612 Pa to 1066.579 Pa.
9. The method of claim 7 , wherein the deposition temperature from 500° C. to 550° C. reduces a presence of Ge-H and (Ge-H 2 ) n in the Ge film.