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Investigation of interfacial impurities in m-plane GaN regrown p-n junctions for high-power vertical electronic devices

Proceedings of SPIE - The International Society for Optical Engineering

Stricklin, Isaac; Monavarian, Morteza; Aragon, Andrew; Pickrell, Gregory P.; Crawford, Mary H.; Allerman, A.A.; Armstrong, Andrew A.; Feezell, Daniel F.

GaN is an attractive material for high-power electronics due to its wide bandgap and large breakdown field. Verticalgeometry devices are of interest due to their high blocking voltage and small form factor. One challenge for realizing complex vertical devices is the regrowth of low-leakage-current p-n junctions within selectively defined regions of the wafer. Presently, regrown p-n junctions exhibit higher leakage current than continuously grown p-n junctions, possibly due to impurity incorporation at the regrowth interfaces, which consist of c-plane and non-basal planes. Here, we study the interfacial impurity incorporation induced by various growth interruptions and regrowth conditions on m-plane p-n junctions on free-standing GaN substrates. The following interruption types were investigated: (1) sample in the main MOCVD chamber for 10 min, (2) sample in the MOCVD load lock for 10 min, (3) sample outside the MOCVD for 10 min, and (4) sample outside the MOCVD for one week. Regrowth after the interruptions was performed on two different samples under n-GaN and p-GaN growth conditions, respectively. Secondary ion mass spectrometry (SIMS) analysis indicated interfacial silicon spikes with concentrations ranging from 5e16 cm-3 to 2e18 cm-3 for the n-GaN growth conditions and 2e16 cm-3 to 5e18 cm-3 for the p-GaN growth conditions. Oxygen spikes with concentrations ~1e17 cm-3 were observed at the regrowth interfaces. Carbon impurity levels did not spike at the regrowth interfaces under either set of growth conditions. We have correlated the effects of these interfacial impurities with the reverse leakage current and breakdown voltage of regrown m-plane p-n junctions.

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TYPE Journal Article YEAR 2018
DOIOSTI

Highly Efficient Solar-Blind Single Photon Detectors

Armstrong, Andrew A.; Klein, Brianna A.; Allerman, A.A.; Baca, A.G.; Crawford, Mary H.; Pickrell, Gregory P.; Perez, Carlos P.; Podkaminer, Jacob; Siegal, Michael P.; Jayawardena, Asanka; Ahyi, Ayayi; Dhar, Sarit

Photodetectors sensitive to the ultra-violet spectrum were demonstrated using an AlGaN high electron mobility transistor with an GaN nanodot optical floating gate. Peak responsivity of 2 x 109 A/W was achieved with a gain-bandwidth product > 1 GHz at a cut-on energy of 4.10 eV. Similar devices exhibited visible-blind rejection ratios > 106. The photodetection mechanism for $β$-Ga2O3 was also investigated. It was concluded that Schottky barrier lowering by self-trapped holes enables photodetector gain.

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TYPE SAND Report YEAR 2018
DOIOSTI
Results 101–125 of 272
Results 101–125 of 272