| 摘要 |
PURPOSE:To use a memory cell by setting the collector potential of the cell at a low level by providing a high-concentration N-type layer adjacent to a P-type base layer. CONSTITUTION:A high-concentration N-type layer 2 and low-concentration N-type layer 3 are formed on a P-type silicon substrate 1. A MOSFET is constituted by forming P-type layers 9 and 10 in the layer 3 separated by a field oxide film 4 and a gate electrode 5 in a gate oxide film. On the other hand, a bipolar transistor which uses the P-type layer 10 as a base and N-type layer 3 as a collector is formed by forming a high-concentration N-type emitter 11 in the layer 10. In addition, a high-concentration N-type layer 12 is formed adjacent to the layer 10. Therefore, the voltage of the bipolar transistor can be suppressed to a low level and desired collector potential can be obtained by controlling the surface concentration of the layer 12. |
