LOW-TEMPERATURE PREPARATION OF DOPED HYDROGENATED AMORPHOUS-SILICON FILMS BY AC-BIASED MICROWAVE ECR PLASMA CVD METHOD

Phospborus and boron doped bydrogenated amorphous silicon films were deposited by microwave electron-cyclotron-resonance (ECR) plasma CVD with an AC (20 kHz) substrate bias. Electrical properties of the films have been investigated. The dark conductivity gradually increased with the increase of AC substrate bias power. Above the 50 W bias power, the conductivities of about 10-6(Ω·cm)-1and about 10-7(Ω·cm)-1were obtained for both P-doped and B-doped films respectively, under the low substrate temperature below 50°C. These doped films were applied to the fabrication of the a-Si:H junction diode with a structure of glass/Cr/pin/Al. A diode quality factor of about 2.2 was evaluated and a ratio of forward current to reverse current of more than 104was obtained at 1.5 V. © 1990 IOP Publishing Ltd.