A heterojunction type compound semiconductor field effect transistor includes
a
channel layer, a first electron supply layer, an electric field strength reducing
layer, a first contact layer, a recess stopper layer, and a second contact layer
sequentially stacked on a compound semiconductor substrate. This transistor has
a double recess structure. The first contact layer is composed of GaAs or InGaAs
doped with n type impurities with a high electron mobility. The electric field
strength reducing layer is composed of intrinsic InGaP.