JPS6442178A - Field effect transistor - Google Patents

Abstract

PURPOSE:To reduce static capacitances created between a rear grounding electrode and a gate electrode, a source electrode and a drain electrode and suppress the degradation of a gain in a radio frequency band as low as possible by drilling a number of holes over the region of a semiconductor substrate including the respective electrode from the rear of the substrate. CONSTITUTION:A number of holes are drilled over the region of a semi- insulating semiconductor substrate 1 including a gate electrode 2, a drain electrode 3 and a source electrode 4. The holes practically reduce the specific inductive capacity of the semi-insulating semiconductor substrate. With this constitution, the static capacitance created between the gate electrode 2 and a rear grounding electrode 8 and the static capacitance created between the drain electrode 3 and the rear grounding electrode 8 can be reduced so that that degradation of the gain in a radio frequency band can be reduced significantly. In other words, a field effect transistor with little gain degradation in the radio frequency band can be realized.