Browsing by Author "Alptekin, E."

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    Low damage etching of GaN surfaces via bias-assisted photoenhanced electrochemical oxidation in deionized water
    (Springer New York LLC, 2007) Alptekin, E.; Yu, H.; Özbay, Ekmel; Aktas, O.
    Properties of GaN surfaces etched by bias-assisted photoenhanced electrochemical (PEC) oxidation in deionized water and subsequent removal of the oxidized material are investigated using Schottky diodes fabricated on etched surfaces. It is demonstrated that with a short anneal at 700°C after removal of the oxide, it is possible to obtain a low damage surface with near ideal breakdown and capacitance-voltage (C-V) characteristics. Good quality Schottky diodes are fabricated on surfaces etched as much as 120 nm. The undercutting of masked surfaces is also demonstrated. Thus, given the band-gap selectivity, the possibility to undercut masked areas, and the low damage surfaces that can be obtained, the process demonstrated in this paper is suitable for use in fabrication of self-aligned GaN bipolar transistor structures.
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    Simulation of GaN and AlGaN static induction transistors
    (Elsevier Science & Technology, 2006) Alptekin, E.; Aktas, O.
    GaN and AlGaN static induction transistors (SITs) are simulated using a two-dimensional self-consistent drift-diffusion simulator incorporating impact-ionization and self-heating effects. The results indicate that GaN SIT devices can have performance comparable to SiC SITs. As compared to GaN SITs, AlGaN SITs will have higher breakdown voltage but smaller maximum current. The power per unit gate width obtainable from GaN and AlGaN SITs are approximately the same, but the maximum power handling capacity of the AlGaN SIT is significantly higher due to bigger optimum load resistance. A comparison of the characteristics of GaN and AlGaN SITs with AlGaN/GaN HEMTs shows that the SIT devices have much lower cut-off frequency and smaller transconductance but can produce higher total output power. © 2006 Elsevier Ltd. All rights reserved.