| 摘要 |
To improve characteristics of a semiconductor device. In a semiconductor device (MISFET) having a gate electrode GE that is formed on a nitride semiconductor layer CH with a gate insulating film GI therebetween, the gate insulating film GI is configured such that the gate insulating film has a first gate insulating film (oxide film formed of a first metal) GIa formed on the nitride semiconductor layer CH, and a second gate insulating film (oxide film formed of a second metal) GIb. The second metal (for instance, Hf) has a lower electronegativity than the first metal (for instance, Al). In this manner, a threshold voltage (Vth) can be shifted in the positive direction by having the electronegativity of the second metal lower than the electronegativity of the first metal. Furthermore, the gate electrode GE is configured such that the gate electrode has a first gate electrode (nitride film formed of a third metal) GEa formed on the second gate insulating film GIb, and a second gate electrode (fourth metal) GEb. Consequently, oxygen is prevented from diffusing to the gate insulating film GI, and fluctuation of the threshold voltage (Vth) can be reduced. |
