| 摘要 |
PURPOSE:To reduce the increase of gate capacitance with the formation of an insulating layer to approximately one fourth by shaping a space between a T-shaped gate and a substrate in a FET. CONSTITUTION:An N-type GaAs active layer 3, to which a recess 10 is formed, onto a GaAs substrate 2, a T-shaped gate 12 consisting of aluminum onto an N-type GaAs active layer 3 and an insulating layer 16 composed of SiO2 through a CVD method are shaped. A protective film 23 consisting of Si3N4 formed through the CVD method is shaped onto the surface of the N-type GaAs active layer 3 and the surface of the T-shaped gate 12, and spaces (air gaps) 17 are formed under the T-shaped gate 12 except a channel section. The dielectric constant of the air gap is made smaller than that of a semiconductor such as SiO2, thus inhibiting the increase of gate capacitance with the formation of the insulating layer composed of SiO2, etc. |
