The Low Leakage Current Density of MIS with SiO2 Film Made by ICP-CVD

Abstract

Thin Film Transistors (TFT) made from high quality semiconductor films can be used in active matrix liquid crystal displays (AMLCD). The properties of the gate oxide are very important in the operation of MIS. In this work, crystallized SiO2 films were deposited at extremely low temperature (90{degree sign}C) by inductively coupled plasma chemical vapor deposition. The results show that the deposition rate increased approximately linearly with applied r.f. power in the ICP-CVD system. Only the (1 11) X-ray diffraction peak appeared in the range of the study. At 1000 Watts, the silicon dioxide film is amorphous which may be attributed to low deposition temperature. The value of the dielectric constant of the MIS varied from 3.75 to 4.05. From the I-V curve it can be seen that the SiO2 thin film has a lower leakage current density when prepared at 1750Watt. The lowest leakage current density obtained in this study was 6.8×10-8A/cm2 @V=1V.