| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem that implantation of holes is reduced and a forward voltage value at a certain current point becomes high, when impurity concentration of a p-type impurity region is reduced for the purpose of shortening time of reverse recovery in a semiconductor apparatus (for example, a pn junction diode), in which a conductivity modulation element is provided on a first main surface of a semiconductor substrate. SOLUTION: In a semiconductor apparatus, a second electrode is selectively contacted with a semiconductor substrate SB. That is, an insulating film having an opening in a second main surface of the semiconductor substrate SB is provided, and the second electrode is provided on the insulating film. The second electrode is contacted with the second main surface of the semiconductor substrate SB via the opening. Total area of the opening is approximately half of the total area of the second main surface of the semiconductor substrate SB. This leads to the extraction of minority carriers (holes) being prevented by the insulating film, to reduce annihilation of the minority carriers near the second electrode. Hence, conductivity modulation effect is enhanced, and as a result, forward voltage VF can be reduced, even in a configuration in which impurity concentration of a p-type impurity region is reduced for the purpose of shortening the time of reverse recovery ttr. COPYRIGHT: (C)2009,JPO&INPIT |
