Solid State Science and Technology, Vol. 12, No. 1 (2004) 59-64
EFFECTS OF ANNEALING ON THE ELECTRO-OPTICAL PROPERTIES OF a- Si:H THIN FILMS DEPOSITED BY D.C. AND PULSED PECVD
Lim Seck Chai, Goh Boon Tong and Saadah Abdul Rahman
University of Malaya,
50603 Kuala Lumpur
Hydrogenated amorphous silicon thin films studied in this work were prepared by d.c. and pulsed PECVD technique at a fixed silane flow-rates of 10 sccm and 40 sccm. The deposition temperature, pressure and power were fixed at 200oC, 0.45 mbar and 1.4 W respectively. The pulsed PECVD system was developed from a modification of the existing d.c. PECVD system with a modulation frequency of 10 kHz. The ON-time and OFF-time was set at 30 seconds. In this work, the effects of annealing on the electro-optical properties of films prepared by both techniques at these flow-rates were investigated. These films were analyzed using optical absorption spectroscopy technique. The results showed that annealing had significant effects on electro-optical properties of these films at annealing temperatures above 300oC mainly due the evolution of hydrogen. The silane flow-rate and the deposition technique also influenced the effects of annealing on the electro-optical properties of these films.
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