INTEGRATION OF N- AND P-CONTACTS TO GaN-BASED LIGHT EMITTING DIODES

Low-resistance Ohmic contacts are essential for the fabrication of electrical devices. While low contact resistance has been achieved to p-type layers or n-type layers separately, contacts are likely to degrade when both types need to be integrated into a single fabrication process, in particular when prior mesa etching is required. We present a solution to the problem, resulting in low-resistance Ohmic contacts on n-type GaN layers without post-deposition thermal anneal, while maintaining the quality of typical p-type contacts. We implement an integrated process for both, n- and p-contacts, involving an oxygen pretreatment to fabricate light emitting diodes with lower series resistance in the contacts and lower voltage drop at high current when compared to separately optimized contacts.