Native GaN Substrates Research Articles

Deep centers in semi‐insulating Fe‐doped native GaN substrates grown by hydride vapour phase epitaxy

AbstractElectrical properties, Fe concentration, and deep centers in semi‐insulating Fe‐doped GaN substrates grown by hydride vapor phase epitaxy (HVPE) were characterized by temperature‐dependent Hall‐effect measurements, secondary ion mass spectroscopy, and thermally stimulated current (TSC) spectroscopy. Five adjacent samples from a low‐[Fe] wafer displayed very high resistivity, dominated by a center at 0.94 eV. At least six traps were observed in the samples by TSC, with trap B (0.56‐0.60 eV) being dominant. A metastable trap A1 at ∼0.82 eV appeared after white‐light illumination at 300 K. A sample from a high‐[Fe] wafer displayed a lower resistivity, dominated by a center at 0.58 eV. The largest TSC peak in this sample was trap A1, although trap B also appeared. These TSC traps are compared with deep‐level‐transient‐spectroscopy traps reported in conductive epitaxial and bulk HVPE‐GaN. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Bandgap engineering of electronic and optoelectronic devices on native AlN and GaN substrates: A modelling insight

Native GaN and AlN substrates cut out of single-crystal boules provide threading dislocations in on-grown III-nitride materials with the density much lower than that observed in structures on conventional sapphire or SiC wafers. The native substrates are also expected to enable an easy choice of growth surface orientation that controls the crystal polarity and, hence, the distribution of polarization charges in a nitride heterostructure. The impact of these factors on the bandgap engineering of advanced electronic and optoelectronic devices is discussed in this paper in terms of numerical simulation with the focus on high-electron mobility transistors and light-emitting diodes.