NOVELTY - The method involves forming an impurity region (110) in a carbide semiconductor region (106), where the impurity region is conductivity type and surrounded by another impurity region (108). A gate electrode (114) is formed over a semiconductor layer with a gate insulating layer (112). A source electrode (118) is formed in contact with the latter impurity region and the former impurity region. A drain electrode (120) is in contact with the semiconductor layer, where the latter impurity region overlaps with a part of the gate electrode.    USE - Method for manufacturing a semiconductor device e.g. bipolar transistor and insulated gate FET, of a solar power generation system.    ADVANTAGE - The source electrode is negatively biased while the drain electrode is positively biased such that the p-n junction formed between the source electrode and the drain electrode is biased in reverse direction, so that leakage current between the source electrode and the drain electrode is reduced. The semiconductor device can dissipate heat efficiently due to the carbide semiconductor that has high thermal conductivity, thus increasing electric current density per unit area in the semiconductor device. The method enables manufacturing the semiconductor device withstanding high voltages by forming part or a channel formation region of a transistor from a carbide semiconductor region so as to form the silicon carbide semiconductor layer by heating the semiconductor substrate or the substrate provided with the semiconductor layer in an atmosphere containing carbide gas, so that a larger apparatus can be used for heat treatment if the area of the semiconductor substrate or the semiconductor layer is increased, thus manufacturing the semiconductor device with the silicon carbide semiconductor without decreasing productivity.    DETAILED DESCRIPTION - The semiconductor layer is made of single crystal silicon and the carbide semiconductor region is made of silicon carbide.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a semiconductor device formed using a semiconductor substrate.    Carbide semiconductor region (106)    Impurity regions (108, 110, 122)    Gate insulating layer (112)    Gate electrode (114)    Source electrode (118)    Drain electrode (120)