| 摘要 |
PURPOSE:To obtain desired current amplification factor of a semiconductor integrated circuit by integrally forming lateral and longitudinal transistors in a bipoalr IC by altering the area of the emitter region apparently upon alteration of the shape of the buried region. CONSTITUTION:A bipolar IC is made of PNP transistors, NPN transistors, and diodes, and PNP transistors 11 for input is formed as below. That is, N<+>-type buried region 20 is formed in a P<-> type Si substrate 23, N-type layer 21 is epitaxially grown on the entire surface, and the layer 21 is formed in an island including the region 20 by the P<+> type region. Then, there are diffused P<+> type region 22 as the collector of the lateral PNP transistor 11 and guard ring of a guard ring Schottky 13 and a P-type region 24 as emitter thereof in the layer 21. In this configuration the region 20 extended underneath the normal region 24 is cut out at the region disposed under the region 24 to set the current amplification factor at a desired value by selecting the length 30 thereof. |
