| CPC H01L 29/8611 (2013.01) [H01L 29/2003 (2013.01); H01L 29/452 (2013.01); H01L 29/66136 (2013.01)] | 10 Claims | 

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               1. A high voltage gallium nitride vertical PN diode, comprising: 
            a high-doped n-type gallium nitride substrate or contact layer; 
                a low-doped n-type gallium nitride drift layer epitaxially grown on the gallium nitride substrate, wherein the drift layer is greater than 10 microns in thickness and has a donor concentration of less than 2×1015/cm3; 
                a p-type region comprising one or more p-type layers epitaxially grown on the drift layer, thereby forming a PN junction with the drift layer; 
                an ohmic cathode contact deposited on the high-doped n-type gallium nitride substrate or contact layer; 
                an ohmic anode contact deposited on the p-type region; and 
                a step-etched multi-zone junction termination extension structure laterally surrounding the anode contact in the p-type region. 
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