Modeling of the Vertical Leakage Current in AlN/Si Heterojunctions for GaN Power Applications

The role of low-resistivity substrate on vertical leakage current (VLC) of AlGaN/GaN-on-Si epitaxial layers has been investigated. AlGaN/GaN high-electron-mobility transistors (HEMTs) grown on both p-type and n-type Si substrates with low resistivity are applied to analyze the vertical leakage mechanisms. The activation energy (Ea) for p-type case is higher than that for n-type at 0–600 V obtained by temperature-dependent current-voltage measurements. An additional depletion region in the region of 0–400 V forms at the AlN/p-Si interface but not for AlN/n-Si. That depletion region leads to a decrease of electron injection and hence effectively reduces the VLC. While in the region of 400–600 V, the electron injection from p-Si substrate increases quickly compared to n-Si substrate, due to the occurrence of impact ionization in the p-Si substrate depletion region. The comparative results indicate that the doping type of low-resistivity substrate plays a key role for VLC.

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Relationship between Al content of AlGaN buffer layer on top of initial AlN nucleation layer on Si and vertical leakage current of AlGaN/GaN high-electron-mobility transistor structures

2016 Compound Semiconductor Week (CSW) [Includes 28th International Conference on Indium Phosphide & Related Materials (IPRM) & 43rd International Symposium on Compound Semiconductors (ISCS) ◽

10.1109/iciprm.2016.7528671 ◽

2016 ◽

Author(s):

Yuya Yamaoka ◽

Kazuhiro Ito ◽

Akinori Ubukata ◽

Yoshiki Yano ◽

Toshiya Tabuchi ◽

...

Keyword(s):

Buffer Layer ◽

Leakage Current ◽

Electron Mobility ◽

High Electron Mobility Transistor ◽

High Electron ◽

Nucleation Layer ◽

High Electron Mobility ◽

Al Content ◽

Vertical Leakage ◽

Algan Buffer

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Investigations of Critical Structural Defects in Active Layers of GaN-on-Si for Power Electronic Devices

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.242.417 ◽

2015 ◽

Vol 242 ◽

pp. 417-420 ◽

Cited By ~ 1

Author(s):

Michael Knetzger ◽

Elke Meissner ◽

Joff Derluyn ◽

Marianne Germain ◽

Jochen Friedrich

Keyword(s):

Leakage Current ◽

Electronic Devices ◽

Carbon Doping ◽

Structural Defects ◽

Power Electronic ◽

Si Substrates ◽

Active Layers ◽

Analytical Scanning Electron Microscopy ◽

Vertical Leakage ◽

Gan On Si

The influence of structural defects in the active layer of GaN-on-Si substrates on the vertical leakage current was studied. The structural defects were analyzed by analytical scanning electron microscopy by means of cathodoluminescence (CL). The leakage current was determined by vertical I-V measurements.Two possibilities were found, which give potential explanations for the variations of the vertical leakage current: i) Threading dislocations, which may partially form leakage paths, were detected by CL imaging. ii) Variations of the carbon doping, which is used to tune GaN to a semi insulating material were revealed by CL spectroscopy.

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