GaN-on-diamond samples were demonstrated using a membrane-based technology. This was achieved by selective area Si substrate removal of areas of up to 1 cm × 1 cm from a GaN-on-Si wafer, followed by direct growth of a polycrystalline diamond using microwave plasma chemical vapor deposition on etch exposed N-polar AlN epitaxial nucleation layers. Atomic force microscopy and transmission electron microscopy were used to confirm the formation of high quality, void-free AlN/diamond interfaces. The bond between the III-nitride layers and the diamond was validated by strain measurements of the GaN buffer layer. Demonstration of this technology platform is an important step forward for the creation of next generation high power electronic devices.

Turn-on voltage instability of beta-gallium oxide ( $\beta $ -Ga2O3) vertical trench Schottky barrier diodes (SBDs) with different fin-channel orientations was investigated. Fins oriented along the [010] direction exhibited the highest turn-on voltage stability and the smallest hysteresis, while fin channels oriented along the [100] direction exhibited the greatest instability. This study suggests that charge trapping at the sidewalls of $\beta $ -Ga2O3 trench SBDs differs based on the fin channel orientation and that fin channels oriented along the [010] direction possess the best electrical characteristics and reliability.

We report on the consistent measurement of gallium incorporation in nominal InAlN layers using various complimentary techniques, underpinned by X-ray diffraction. Nominal InAlN layers with similar growth conditions were prepared, and the change in unintended Ga content in the group III sublattice ranged from ∼24% to ∼12% when the total reactor flow rate was increased from 8000 to 24 000 standard cubic centimetres per minute. Ultra-thin InAlN/GaN HEMT layers were grown in a clean reactor to minimize Ga auto-incorporation, and measured using X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The implications of Ga incorporation in InAlN layers within optoelectronic and power devices is discussed.

InAlN epilayers deposited on thick GaN buffer layers grown by metalorganic chemical vapour deposition (MOCVD) revealed an auto-incorporation of Ga when analysed by wavelength dispersive x-ray (WDX) spectroscopy and Rutherford backscattering spectrometry (RBS). Samples were grown under similar conditions with the change in reactor flow rate resulting in varying Ga contents of 12–24%. The increase in flow rate from 8000 to 24000sccm suppressed the Ga auto-incorporation which suggests that the likely cause is from residual Ga left behind from previous growth runs. The luminescence properties of the resultant InAlGaN layers were investigated using cathodoluminescence (CL) measurements

Aluminium gallium nitride/gallium nitride (AlGaN/GaN)-based superlattice castellated field-effect transistors are a potential basis for high-power radiofrequency amplifiers and switches in future radars. The reliability of such devices, however, is not well understood. Here we report transistor latching in multichannel GaN transistors. At the latching condition, drain current sharply transits from an off-state value to a high on-state value with a slope less than 60 mV per decade. Current–voltage measurements, simulations and correlated electroluminescent emission at the latching condition indicate that triggering of fin-width-dependent localized impact ionization is responsible for the latching. This localization is attributed to the presence of fin-width variation due to variability in the fabrication process. The latching condition is reversible and non-degrading, and we show that it can lead to improvement in the transconductance characteristics of transistors, implying improved linearity and power in radiofrequency power amplifiers.