Nitride based semiconductor device and method for manufacturing the same

A method for manufacturing a nitride-based semiconductor device, comprising the steps of:

• forming a semi-insulating GaN layer on a substrate;
• forming a protective layer on one side of the semi-insulating GaN layer on which a surface acoustic wave filter is to be formed;
• forming an AlGaN layer on the other side of the semi-insulating GaN layer on which a heterostructure field effect transistor is to be formed;
• removing the protective layer by wet etching;
• and
• forming a plurality of electrodes for a heterostructure field effect transistor on the AlGaN layer, and forming a plurality of electrodes for a surface acoustic wave filter on the region of the semi-insulating GaN layer where the protective layer is removed.