| 摘要 |
PURPOSE:To improve and stabilize the characteristics of an FET by forming an Si2N4 film by a plasma CVD method by a glow discharge with mixture gas of SiH4-NH3-N2-H2 as a gate insulating film. CONSTITUTION:An Mo gate electrode 2 which has approx. 1,000Angstrom of thickness is formed on a glass plate 1, an Si3N4 film 3 is formed by a plasma CVD method by the prescribed glow discharge, further an amorphous polysilicon layer 6 which has approx. 3,000Angstrom of thickness is selectively superposed, aluminum is deposited and electrodes are isolated by photoetching to obtain a channel of the prescribed length and width, thereby completing an FET. The molar ratio of the mixture gas when forming the film 3 is selected to the ranges of NH3/SiH4=2- 10, N2/SiH4=4-20, H2-SiH4=1-20. Thus, when gas produced by adding H2 gas to the mixture gas of SiH4-NH3-N2 is used to form an Si3N4 gate insulating film by a plasma CVD method, the FET which has the small variations in the threshold voltage and the drain current, small drain-off current, low cost and preferable characteristics can be obtained. |
