Jasruddin, W.W. Wenas, T. Winata, M. Barmawi
The growth of hydrogenated amorphous silicon (a-Si:H) and hydrogenated amorphous silicon nitride (a-SiN:H) films was studied by plasma enhanced chemical vapor deposition (PECVD) method. 10% silane (SiH 4) diluted in hydrogen (H 2) gas and 100% ammonia (NH 3) gas were used as gas sources. The optical band-gap and deposition rate of a-Si:H film were found varied from 1.70 to 1.95 eV and 51 to 84 A 0/min, respectivelly, when the SiH 4 gas flow rate varied from 5 to 11 seem. The widest optical bandgap of a-SiN:H films whichis of 3.69 eV and lowest dark conductivity of 1.07×10 -11 Scm -1 were obtained at NH 3 gas fraction of 60% at SiH 4 flow rate 7 seem. It is also shown that wider optical bandgap of a-SiN:H can be obtained at the flow rate of SiH 4 gas of 5 seem where its value reaches 3.97 eV at NH 3 gas fraction of 25%, whilst its dark conductivity reaches lower value of 1.05×l0 -12 Scm -1. The application of the films as an insulator gate in the thin film transistor (TFT) device was also studied. The lowest dark conductivity of the a-SiN:H film resulted in a better device thereshold voltage. © 2000 IEEE.
Laboratory for Electronic Material Physics, Department of Physics, Institut Teknologi Bandung, Indonesia; Department of Physics, Universitas Negeri Makassar, Indonesia
