| 摘要 |
PURPOSE:To obtain a semiconductor device having high performance by isolating n- type low density mesa type region via p-type layer into upper and lower layers, coating the peripheral edge in insulation and generating a drift current substantially in balance with diffusion current dut to minority carrier in the upper layer. CONSTITUTION:An n-epitaxial layer 11 is formed on an n<+>-type silicon substrate 10, a Si3N4 mask 12 is formed thereon, the layer 11 is selectively etched to form a mesa type region. Then, a thick oxide film 13 is formed, B ion is implanted to the portion excluding the mask 12 to form a p-type base layer 14. P is diffused in the upper layer 11b to form an n<+>-type layer 15 as an emitter electrode pickup layer. A collector electrode 10 is formed at the n-type substrate 10, and a base electrode is formed at the layer 14. Since the emitter is low density, the minority carrier diffusion distance is larger than the emitter thickness, an n<+>n and pn-junctions are formed in the emitter layer to form an electric field for producing a drift current balanced with the diffusion current of the minority carrier in the emitter to increase the gain and to enable low noise and high withstand voltage. |
