| 摘要 |
A field effect type semiconductor device is disclosed wherein a channel is easily depleted just under a gate electrode to implement an E-mode, but a channel is hard to be depleted just under a gate recess region so that the transconductance gm and the cutoff frequency fT can be set to sufficiently high values. The present device includes a first etching stop layer Schottky contacting with an end face of the gate electrode and a second etching stop layer extending to a position in the proximity of a side face of the gate electrode. The first etching stop layer is formed from a material which is easily depleted (one of materials of a group including InAlP, InP, InAsP, InSbP, InAlAsP, and InAlSbP), and the second etching stop layer is formed from a material which is hard to be depleted (one of materials of a group including InGaP, InGaAsP, InGaSbP).
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