SEMICONDUCTOR DEVICE AND POWER AMPLIFIER CIRCUIT

PROBLEM TO BE SOLVED: To provide a semiconductor device capable of improving the reliability while maintaining a high power addition efficiency both at low output power and at high output power.SOLUTION: A semiconductor device 100A comprises: a semiconductor substrate 1 that has first and second principal surfaces opposed to each other; a first bipolar transistor Q1 formed on the first principal surface side of the semiconductor substrate, and that has a first emitter layer 5a; and a second bipolar transistor Q2 formed on the first principal surface side of the semiconductor substrate, and that has a second emitter layer 5b, and an emitter ballast resistive layer 8 laminated in a normal line direction of the first principal surface from the second emitter layer.SELECTED DRAWING: Figure 2 【課題】低出力電力時及び高出力電力時の双方において高い電力付加効率を維持しつつ信頼性が向上する半導体装置を提供する。【解決手段】半導体装置１００Ａは、対向する第１及び第２主面を有する半導体基板１と、半導体基板の第１主面側に形成され、第１エミッタ層５ａを有する第１バイポーラトランジスタＱ１と、半導体基板の第１主面側に形成され、第２エミッタ層５ｂと、当該第２エミッタ層より第１主面の法線方向に積層されたエミッタバラスト抵抗層８と、を有する第２バイポーラトランジスタＱ２と、を備える。【選択図】図２