Schottky performance variation on r -plane and c -plane of GaN micro truncated-pyramid grown by selective area MOCVD

The electric properties of Pt Schottky contacts on semipolar r-plane and polar c-plane of GaN micro truncated-pyramid are compared. The Schottky diodes of the inclined r-plane sample illustrate a relatively inferior rectified performance than that of the top c-plane GaN in term of the lower Schottky barrier heights, larger ideality factor and reverse leakage current. By depositing Pt metal on the dislocation-free area of the top of GaN micro pyramid, the Schottky performance of r-plane GaN can be slightly improved, but still shows much larger reverse leakage current than that of c-plane GaN. It is found that polarization-related surface states and incorporation of donor impurities, rather than dislocation, should mainly contribute to this remarkable electric discrepancy of the planes.