| 摘要 |
PROBLEM TO BE SOLVED: To realize improvement in both of the S/N of a JFET and the transient characteristics of drain current simultaneously, in a semiconductor device equipped with the JFET used for a microphone or the like. SOLUTION: In the manufacturing method of a semiconductor device, a JFET210 as a variable impedance element is connected between the gate of a main JFET100 and a source. In the transition period just after impressing a drain voltage, the channel impedance of the JFET210 is low so that the transitional drain current may be promptly absorbable. On the other hand, after the drain current is in a steady state, the channel impedance of the JFET210 is made high-impedance so as to attain low noise by reducing leak (useless electric discharge) of a signal component. COPYRIGHT: (C)2006,JPO&NCIPI
|
