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We report on the investigation of lattice matched InAlN/GaN MOS-HEMT structures prepared by thermal oxidation at 800 °C in oxygen atmosphere for two minutes. The gate leakage current was reduced by two orders of magnitude. Pulse measurements showed lag effects similar to what is observed for devices without oxidation, indicating a high quality native oxide. The MOS-HEMT showed no degradation in the small signal characteristics and yielded a power density of 5 W/mm at 30 V drain voltage at 10 GHz, power added efficiency of 42% and Ft and Fmax of 42 and 61 GHz respectively, illustrating the capability of such MOS-HEMT to operate at high frequencies. [ABSTRACT FROM AUTHOR]

Short-channel punch-through effects are demonstrated in 0.17 μm gate length AlGaN/GaN single heterojunction field-effect transistors. These take the form of a high output conductance and the strong dependence of pinch-off voltage on drain voltage. It is shown by simulation that they can be explained by poor confinement of charge at the AlGaN/GaN interface resulting in current flow within the bulk of the GaN layer. This is caused by there being a concentration of only ∼ 1.5 × 1016 cm-3 deep levels in the insulating GaN buffer layer. It is found that a net acceptor density of around 1017 cm-3 is required to ensure suppression of short-channel effects. [ABSTRACT FROM AUTHOR]

This review explores the processes involved in enhancing AlN film quality through various magnetron sputtering techniques, crucial for optimizing performance and expanding their application scope. It presents recent advancements in growing AlN thin films via magnetron sputtering, elucidating the mechanisms of AlN growth and navigating the complexities of thin-film fabrication. Emphasis is placed on different sputtering methods such as DC, RF, pulsed DC, and high-power impulse DC, highlighting how tailored sputtering conditions enhance film characteristics in each method. Additionally, the review discusses recent research findings showcasing the dynamic potential of these techniques. The practical applications of AlN thin films, including wave resonators, energy harvesting devices, and thermal management solutions, are outlined, demonstrating their relevance in addressing real-world engineering challenges. [ABSTRACT FROM AUTHOR]

In this paper, a new method for evaluating hot-electron degradation in p-GaN gate AlGaN/GaN power HEMTs is proposed. The method exploits a commercial parameter analyzer to study VTH and RON drifts induced by on-state stress at VDS = 50 V. The results show that VTH drift and part of the RON degradation induced by the on-state stress are recoverable and likely due to the ionization of C-related acceptors in the buffer. This was confirmed by a preliminary characterization of C-related buffer traps. Conversely, the remaining part of RON degradation (not recovered in 1000 s) was strongly affected by the surface treatment. The current level set during on-state stress affected the amount of non-recoverable degradation, confirming the involvement of hot electrons. Thanks to the monitoring of the parameters' recovery, the proposed method provides important insights into the physical mechanisms governing the parameters' degradation. This extends the capabilities of state-of-the art systems, without the need for custom setup development. [ABSTRACT FROM AUTHOR]