Patent ID: 7470958

Claim:
A semiconductor device comprising: an element forming layer including a plurality of nitride semiconductor layers formed on a substrate and having a heterojunction interface; a field effect transistor having a source electrode, a drain electrode and a gate electrode and formed on said element forming layer; and plural diodes that include a p-type nitride semiconductor layer selectively formed on said element forming layer and an ohmic electrode spaced from said p-type nitride semiconductor layer and formed on said element forming layer and have a pn junction formed between an n-type region of a two-dimensional electron gas generated on said heterojunction interface and a p-type region of said p-type nitride semiconductor layer, wherein at least two of said plural diodes are electrically connected to each other in series and form a diode pair with anodes thereof electrically connected to each other, said diode pair includes said p-type nitride semiconductor layer that is one in number and is a common anode of said two diodes, and said ohmic electrode that is two in number formed with said p-type nitride semiconductor layer sandwiched therebetween, said two ohmic electrodes are formed on the element forming layer in different regions opposite to each other with said p-type nitride semiconductor layer sandwiched therebetween, and one of said ohmic electrodes is electrically connected to said gate electrode and forms a current path for allowing an excessive current caused in said gate electrode to pass.