SEMICONDUCTOR DEVICE AND FABRICATION THEREOF

摘要

PURPOSE:To prevent any overetching from being caused and hereby prevent the diffusion of foreign elements from a substrate by bringing at least part of a metal wiring extending from an impurity region into close contact with a silicon nitride film on an aluminum oxide film. CONSTITUTION:A silicon layer (first silicon nitride layer) 102 is formed for preventing any different element from a substrate from diffusing into a TFT. An undercoat silicon oxide layer 103 is provided to prevent the TFT from back leaking. Then, after a semiconductor region 104 is formed, a gate insulating film 105 and aluminum oxide or a silicon nitride layer (second aluminum oxide or a silicon nitride layer) 106 are formed. Thereafter, a wiring 107 and a gate electrode 108 are formed using a first metal layer. Further, an impurity region is formed on the semiconductor region 104 inn a self-aligning manner. Such formation of a barrier layer of silicon nitride or aluminum oxide results in the prevention of overetching and the improvement of the yield of devices.