Abstract: An insulated gate type field effect transistor for high power which has a low conductivity region surrounding a drain region and an offset gate region having a further lower conductivity adjoined thereto, wherein the length and impurity concentration are designed according to the electric characteristics of the transistor. A combination of P channel and N channel type transistors having substantially the same electric characteristics and an audio amplifying circuit using the combination are also disclosed.

Abstract: An insulated-gate semiconductor device wherein a first region is formed in the surface of a semiconductor substrate, the first region having a conductivity type opposite to that of the substrate, two insulated-gate FET's are formed within the first region, the drain of the first insulated-gate FET and that of the second insulated-gate FET are made common, the drains are electrically connected to the first region, and the gate of the first insulated-gate FET and the source of the second insulated-gate FET, and the gate of the second insulated-gate FET and the source of the first insulated-gate FET are respectively connected, thereby to prevent the occurrence of a negative resistance.

Abstract: In an insulated gate field effect transistor having a source region and a drain region of the P-conductivity type which are disposed in surface portions of a semiconductor substrate of the N-conductivity type in a manner to be spaced apart from each other, a gate electrode being disposed through an insulating film on the substrate between the source region and the drain region, an insulated gate field effect transistor wherein said drain region is disposed apart from said gate electrode, two regions of an intermediate region and a high resistance region which are of the P-conductivity type and which successively extend from said drain region towards the side of said gate electrode are disposed in surface portions of the substrate situated between said drain region and said gate electrode, said intermediate region having an impurity concentration lower than that of said drain region, said high resistance region having an impurity concentration lower than that of said intermediate region, and a source electrode