SEMICONDUCTOR DEVICE

摘要

A semiconductor device has: a GaN semiconductor layer (15) formed on a substrate (10); a gate insulating film (18) composed of an aluminum oxide formed on the surface of the GaN semiconductor layer (15) by using an ALD apparatus; and a gate electrode (24) formed on the gate insulating film (18).  The carbon concentration of the gate insulating film (18) is 2×1020/cm3 or less.  In the semiconductor device, a leak current in the gate insulating film is suppressed and stable FET characteristics can be obtained. The gate insulating film (18) composed of the aluminum oxide is formed by an ALD method by using TMA and O3 having high oxidizing power.  Thus, the carbon concentration in the gate insulating film (18) is reduced and the leak current can be suppressed.