| 摘要 |
PURPOSE:To obtain a P-well resistor of an always stabilized value in spite of an external factor by a method wherein an N type impurity with density thicker than a substrate density is injected into a P-well resistive region. CONSTITUTION:An N layer (thicker in density than the substrate by more than one figure) is formed on the N<->-substrate, and the P-well resistor 16 is burried between the N<->-substrate and the N layer 17. The N<->-substrate is applied the highest potential which is applied to CMOSIC, so that the N layer 17 is given the highest potential and the P-well resistor 16 is kept from being formed with channels due to an Al layer 12. For this reason, the value of the P-well resistor 16 is kept always constant even the external factor exists. For the formation of the N layer 17, the ions are allowed to selectively independently be injected after the formation of the P-well resistor 16 and otherwise, to be injected at the same time when sources and drains of N-channel MOSFET are formed. Thus, the ideal P-well resistor 16 thereon with the N layer 17. |
