Due to lack of suitable lattice-matched substrates, III-nitride films typically contain a high d. of defects. Hence, spatially resolved techniques are needed to understand the influence of defects on materials properties and device performance. In this paper, we show two examples of applying scanning probe microscopies to investigate defect dominated electronic transport in GaN. We find that the transport in the highly conducting interfacial region in hydride vapor phase epitaxially grown films cannot be explained by electrons in the intrinsic conduction band of GaN. Rather, our results point to the co-existence of a donor impurity band and compensating acceptors, arising from excess oxygen in the region and the defective microstructure at the GaN/sapphire interface. We also show that the reverse bias leakage current in macroscopic GaN Schottky diodes insensitive to barrier height. Scanning current-voltage images reveal that dislocations with a screw component are responsible for the excess reverse bias leakage.
|Proceedings - Electrochemical Society
|Symposium on III-Nitride Based Semiconductor Electronic and Optical Devices and Thirty-Fourth State-of-the-Art Program on Compound Semiconductors (SOTAPOCS XXXIV)
|25/03/01 → 30/03/01
- gallium nitride defect electronic transport scanning probe microscopy