| abstract |
A SiO 2 film may become contaminated by carbon (C) when the SiO 2 film is to be formed on a semiconductor substrate using TEOS (tetraethylorthosilicate: Si (OC 2 H 5 ) 4 ). Carbon can function as a fixed charge in the SiO 2 film. For example, when carbon (C) contaminates the SiO 2 film serving as as a gate insulating film of a metal–oxide–semiconductor field-effect transistor (MOSFET), there is the problem in that the gate threshold voltage (V th ) fluctuates. Provided is a semiconductor device which uses a gallium nitride semiconductor layer, wherein the semiconductor device has at least a portion provided in direct contact with the gallium nitride layer, and is provided with a silicon dioxide film having impurity atoms, the silicon dioxide film containing, as the impurity atoms, carbon at a concentration greater than 0 cm –3 and less than 2E+18 cm –3 , and gallium at a concentration of 1E+17 cm –3 or less. |