SEMICONDUCTOR DEVICE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor device which has a varactor diode, having a sufficiently satisfactory wide capacitance range and linearity of capacitance variation to a control voltage, formed on one semiconductor substrate together with other elements and a manufacturing method for a semiconductor device which can manufacture such a semiconductor device at low cost without altering processes of forming other elements as much as possible as to a semiconductor device which has a transistor and a varactor diode on one semiconductor substrate and a manufacturing method for such a semiconductor device. SOLUTION: A process of introducing impurities of a 1st conductivity into only a 2nd region where the varactor diode is formed to the processes of forming other elements and diffusion is carried out in an existing heat-treating process to form a 1st conductivity diffusion layer 106 which contacts the reverse surface of a 2nd conductivity diffusion layer 107.