| CPC H01L 29/7786 (2013.01) [H01L 29/2003 (2013.01); H01L 29/205 (2013.01); H01L 29/66462 (2013.01)] | 20 Claims | 

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               1. A Group III-nitride (III-N) transistor, comprising: 
            a channel layer comprising a first III-N material; 
                a polarization layer over the channel layer, wherein the polarization layer is a second III-N material with more Al than the first III-N material; 
                a p-type layer over the polarization layer, wherein the p-type layer is a third III-N material comprising a greater concentration of a P-type impurity than either the channel layer or the polarization layer; 
                a spacer layer between, and in contact with, the polarization layer and the p-type layer, wherein the spacer layer is the third III-N material, but with a lower concentration of the P-type impurity than the p-type layer; 
                a gate terminal over the spacer layer; and 
                source and drain terminals coupled to the channel layer. 
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