High‐performance a‐SiGe:H thin film prepared by plasma‐enhanced chemical vapor deposition with high plasma power for solar‐cell application

Abstract

Hydrogenated amorphous silicon germanium (a‐SiGe:H) thin films were prepared by a 13.56‐MHz plasma‐enhanced chemical vapor deposition (PECVD) method. The optical, optoelectronic, and microstructure properties of the a‐SiGe:H thin films prepared with different plasma powers were investigated systematically by transmission, photo/dark conductivity, Raman, and Fourier transform infrared (FTIR) spectroscopy measurements. It was found that when the deposition pressure was high and the hydrogen (H2) dilution ratio ([H2]/([SiH4] + [GeH4])) was low, an appropriate high plasma power could enlarge the optical bandgap (Eg) by reducing the Ge content in the thin film, enhance the film photosensitivity by improving the film microstructure, and increase the film growth rate. As a demonstration, excellent a‐SiGe:H thin film with Eg of 1.5 eV, the photosensitivity of above 104 and a growth rate of 6.6 Å s−1 was successfully fabricated for the solar‐cell application with a plasma power density of 400 mW cm−2, a deposition pressure of 3 Torr, and a H2 dilution ratio equal to 3 at 220 °C. The underlying mechanism was further analyzed.

Effect of rapid thermal annealing on crystallization and stress relaxation of SiGe nanoparticles deposited by ICP PECVD

“…3 Indeed, Si-Ge compounds provide exibility during the growth phase to engineer their bandgap making them promising candidates for many applications such as solar cells and optoelectronics applications. [4][5][6][7] Additionally, they are also suitable for light emitters, photodetectors and on-chip optical interconnects. 8,9 Plasma enhanced chemical vapor deposition (PECVD) was also reported as a viable pathway to fabricate Si-Ge compounds with additional benet of demonstrating higher deposition rates at a signicantly lower temperatures rate while enabling the additional capability of engineering the composition through gas mixture control providing some capability to tune the strained Si-Ge layer bandgap.…”