High electron mobility transistor and fabricating method of the same

A fabricating method of a high electron mobility transistor, comprising:

• providing a substrate;
• forming a channel layer, an active layer, a P-type group III-V compound material layer, a metal compound material layer, a hard mask material layer and a photoresist from bottom to top to cover the substrate;
• patterning the photoresist to form a patterned photoresist;
• performing a dry etching process to etch the hard mask material layer and the metal compound material layer to transform the hard mask material layer into a hard mask and the metal compound material layer into a metal compound layer by taking the patterned photoresist as a first mask, wherein a spacer surrounds the patterned photoresist, the hard mask and the metal compound layer, and the spacer is generated by by-products which are formed during the dry etching process;
• and
• after the dry etching process, etching the P-type group III-V compound material layer by taking the spacer and the patterned photoresist as a second mask;
• and
• removing the spacer, the patterned photoresist and the hard mask.