Sharp Kabushiki Kaisha Corporation

Hisao Ichijoh

Akio Nakajima

Masaru Kubo

Masayuki Fukumi

Norihisa Fujii

A nitride semiconductor device includes a second insulating film () covering at least a drain electrode () and a thermal stress reducer that reduces thermal stress in a place where thermal stress that is generated between the drain electrode () and the second insulating film () reaches its maximum at the time of a load short. The thermal stress reducer () is a drain field plate portion () formed by an extension of an upper part of the drain electrode () toward a source electrode ().

Nitride semiconductor device

Provided is a composite semiconductor device that has a low on-resistance and a high load-short-circuit resistance. In a composite semiconductor device () including a normally-on first FET (Q) and a normally-off second FET (Q) that are cascode-connected to each other. In a case where a voltage applied to a drain of the first FET (Q) is 400 V, a relation of the following expression is satisfied: where a time elapsed after short circuit T represents a time elapsed after a time at which a load connected to the composite semiconductor device () starts to be short-circuited, RonQrepresents a value of an on-resistance of the second FET, VTHQrepresents a threshold voltage of the first FET, Idmaxrepresents a drain current of the first FET in a saturated state of the first FET when a gate voltage of the first FET is 0 V, and Idmax represents a drain current limited to an extent that breakdown of the first FET is prevented for the time elapsed after short circuit T of at least 2 &#x3bc;sec.

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Kanazawa, Japan

Hisao Ichijoh