Patent ID: 7081799

Claim:
An oscillation circuit using a bipolar transistor as an oscillation amplifier, the bipolar transistor comprising: a semiconductor substrate; a transistor operation region formed on the semiconductor substrate; an insulating film formed so as to cover a surface of the semiconductor substrate; a lead line led to a surface of the insulating film therethrough from the transistor operation region; a pad for wire bonding connected to the lead line; and a capacitance adjustment line connected to the pad, wherein the semiconductor substrate is an N + /N type collector substrate, a collector electrode is formed on a reverse surface of the collector substrate, the pad is formed on a surface of the collector substrate as an emitter pad and a base pad, by adjusting an area of the capacitance adjustment line connected to at least one of the base pad and the emitter pad, a capacitance value of at least one of a corresponding collector-base capacitor and collector-emitter capacitor is adjusted, and at least a part of a capacitor contributing to an oscillation operation is composed of a parasitic capacitor formed between the capacitance adjustment line and the collector electrode opposed thereto.