Presentation
5 March 2019 Investigation of Mg and Si doping at different temperature for multi-color micro-LEDs with tunnel junctions (Conference Presentation)
Yoann Robin, Quentin Bournet, Markus Pristovsek, Yamina Andre, Hiroshi Amano
Author Affiliations +
Abstract
We demonstrate the fabrication of 100 x 100µm2 nitride-based tricolor micro-LEDs. While the optical properties of the devices are very promising, the electrical characterizations show large penalty voltage due to the introduction of compensating defects in the p-GaN layers upon plasma etching. Therefore, we consider replacing the p-GaN layers by p+/n+ tunnel junctions. We analyzed the surface morphology and the Mg, Si, H and C concentration of different p/n junctions grown at different temperature. SIMS results show the C concentration drastically increases from 10^16/cm3 at 1100°C to about 10^17/cm3 at 975°C without significantly affecting the electrical properties of both p- and n-type layers. However, the decomposition of tetramethylsilane (TMSi) strongly depends on the growth temperature, and thus the Si/Ga ratio has to be carefully controlled with temperature. The Mg shows a strong memory effect in the n-side since its concentration is slowly decaying of only one decade after 50nm from the p/n interface. The pining of the Fermi level, close to the conduction band in the n-GaN, destabilizes the Mg-H complex and allows the Mg to be activated (Mg/H<<1). In addition, at the high Mg/Ga and Si/Ga ratio typically required in p+/n+ tunnel junction, we observed a change of the GaN surface morphology with the promotion of inversion domains and 3D growth respectively, whatever the growth temperature. Based on these data, we show that a p+/n+ tunnel junction is a trade off between high structural and electrical quality.
Conference Presentation
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yoann Robin, Quentin Bournet, Markus Pristovsek, Yamina Andre, and Hiroshi Amano "Investigation of Mg and Si doping at different temperature for multi-color micro-LEDs with tunnel junctions (Conference Presentation)", Proc. SPIE 10918, Gallium Nitride Materials and Devices XIV, 109181U (5 March 2019); https://doi.org/10.1117/12.2506959
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KEYWORDS
Magnesium

Silicon

Doping

Gallium nitride

Interfaces

Optical properties

Plasma etching

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