Semiconductor device, power-supply unit, amplifier and method of manufacturing semiconductor device

1. A semiconductor device, comprising:

a semiconductor layer formed above a substrate;

an insulating film formed on the semiconductor layer; and

an electrode formed on the insulating film, wherein

the insulating film has a membrane stress at a side of the semiconductor layer lower than a membrane stress at a side of the electrode.

2. The semiconductor device as claimed in claim 1 , wherein

the insulating film includes a first insulating film and a second insulating film laminated on the first insulating film, and

the first insulating film has a membrane stress lower than a membrane stress of the second insulating film.

3. The semiconductor device as claimed in claim 1 , wherein

the insulating film is formed by an amorphous film, wherein carbon is a chief ingredient of the amorphous film.

4. The semiconductor device as claimed in claim 1 , wherein

the insulating film is formed by an amorphous film, wherein carbon is a chief ingredient of the amorphous film, and

a concentration of any one of nitrogen, oxygen, hydrogen and fluorine included in the insulating film is higher at a side of the semiconductor layer than that at a side of the electrode.

5. The semiconductor device as claimed in claim 2 , wherein

the insulating film is formed by an amorphous film, wherein carbon is a chief ingredient of the amorphous film, and

a concentration of any one of nitrogen, oxygen, hydrogen and fluorine included in the first insulating film is higher than the concentration included in the second insulating layer.

6. The semiconductor device as claimed in claim 5 , wherein

a film density in the second insulating film is equal to or greater than 2.6 g/cm 3 and equal to or less than 3.56 g/cm 3 .