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Vertical Current Transport in AlGaN/GaN HEMTs on Silicon: Experimental Investigation and Analytical Model

Remesh, Nayana and Mohan, Nagaboopathy and Kumar, Sandeep and Prabhu, Prabhu and Guiney, Ivor and Humphreys, Colin J and Raghavan, Srinivasan and Muralidharan, Rangarajan and Nath, Digbijoy N (2019) Vertical Current Transport in AlGaN/GaN HEMTs on Silicon: Experimental Investigation and Analytical Model. In: IEEE TRANSACTIONS ON ELECTRON DEVICES, 66 (1). pp. 613-618.

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Official URL: https://doi.org/10.1109/TED.2018.2882533


We investigate the vertical leakage mechanism in metal-organic chemical vapor deposition-grown carbon (C)-doped AlGaN/GaN High Electron Mobility Transistors (HEMTs) on 6-in silicon wafer. Substrate bias polarity-dependentI-V-s, temperature-dependentfitting, and band diagram analysis pointed to the Poole-Frenkel (P-F) type of conduction mechanism for vertical transport in the devices with breakdown as high as 580 V for a buffer of 4 mu m. Trap activation energy of 0.61 eV was estimated from the P-F fitting which matches well with values reported in the literature. We propose that higher dislocation density leads to shallower traps in the buffer and build an analytical model of dislocation-mediated vertical leakage around this. The variation in leakage as a function of dislocation density at a given field is predicted and is found to be the most abrupt in the range from similar to 10(7) to similar to 10(9) cm(-2) of dislocation density. This can be attributed to a sharp decrease in trap activation energy in the above range of dislocation density, possibly due to complex formation between point defects and dislocations.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Keywords: 2-D electron gas; AlGaN; high-electron mobility transistor (HEMT); hopping conduction; Poole-Frenkel (P-F); vertical leakage
Department/Centre: Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited: 28 Jan 2019 09:20
Last Modified: 28 Jan 2019 09:20
URI: http://eprints.iisc.ac.in/id/eprint/61479

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