| 摘要 |
PURPOSE:To obtain a Darlington transistor with improved breakdown strength by a method wherein the base region scheduled region of the front transistor is formed in a recess, and then the base width is changed. CONSTITUTION:The front transistor 1 and the rear transistor 2 have the base region and the collector region in common, and the transistor 1 is formed in a recess on the surface of the base region, accordingly formed thinner than the base region of the transistor 2. Since the (P type) impurity density of the surface is low, the depth xj1 of an emitte region next formed by diffusion is larger than the xj2 of the transistor 2. The base width WB1 of the transistor 1 becomes smaller over the difference of levels on the surfaces of the base regions compared with the base width WB2 of the transistor 2. The sustaining voltage of the transistor 1 can be set by the extension of the transistor 1 base width and adjusted by the etching amount. |
