Semiconductor device and semiconductor circuit including the device

A semiconductor device is disclosed. The semiconductor device includes a second conductive type substrate including a first first-conductive-type doping layer and a plurality of devices on the second conductive type substrate, wherein a first device of the devices includes a first nitride semiconductor layer on the first first-conductive-type doping layer, a second nitride semiconductor layer brought together with the first nitride semiconductor layer to form a first heterojunction interface, between the first first-conductive-type doping layer and the first nitride semiconductor layer, a first contact electrically connected to the first heterojunction interface, and a contact connector electrically connecting the first contact to the first first-conductive-type doping layer.