| 摘要 |
PURPOSE:To enable to perform a high speed switching operation while obtaining withstand voltage between an emitter and a base by setting to satisfy the specific unequality between the impurity density and the thickness of the first base layer. CONSTITUTION:Be is, for example, doped as an impurity on a collector layer 12 in a relatively high impurity density p type GaAs second base layer 132, which is epitaxially grown. The thickness of the second base layer 132 is 1,000Angstrom or lower to perform a high speed switching operation. Then, p<-> type GaAs first base layer 131 of low impurity density and then n<+> type Ga1-xAlxAs emitter layer 14 of high impurity density are epitaxially grown. At this time the relation between the density NB and the thickness W of the fist base layer 131 is set to satisfy the unequality (1). Finally, the periphery is removed except the center of the emitter by etching, the surfaces of the second base layer 132 is exposed, thereby completing the electrodes 14, 15, 16, 17 of the collector, base and emitter. |
