Metal Organic Vapor Phase Epitaxy of Thick N-Polar InGaN Films

Nirupam Hatui,Stacia Keller,Shubhra S Pasayat,Athith Krishna,Umesh K Mishra

doi:10.3390/electronics10101182

Nirupam Hatui, Stacia Keller + Show 3 more

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https://doi.org/10.3390/electronics10101182

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Journal: Electronics	Publication Date: May 15, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: University of California, Santa Barbara

Abstract

Hillock-free thick InGaN layers were grown on N-polar GaN on sapphire by metal organic vapor phase epitaxy using a digital growth scheme and H2 as surfactant. Introducing Mg to act as an additional surfactant and optimizing the H2 pulse time, In compositions up to 17% were obtained in 100 nm thick epilayers. Although Mg adversely affected the In incorporation, it enabled maintenance of a good surface morphology while decreasing the InGaN growth temperature, resulting in a net increase in In composition. The parameter space of growth temperature and Mg precursor flow to obtain hillock-free epilayers was mapped out.

Highlights

The (In,Ga)N alloy system is attractive for various optoelectronic and electronic applications due to its tunable bandgap ranging from 0.7 to 3.4 eV [1]
Growing InGaN with higher In compositions by metal organic vapor phase epitaxy (MOVPE) is challenging because of the low thermal stability of InN, which results in the growth temperature of InGaN films being significantly lower than the optimal growth temperature of GaN [9]
The growth temperature of InGaN layers has to be lower, the higher the targeted In content [10]

Summary

Introduction

The (In,Ga)N alloy system is attractive for various optoelectronic and electronic applications due to its tunable bandgap ranging from 0.7 to 3.4 eV [1]. Thick InGaN films are especially of interest as relaxed base layers for InGaN based optoelectronic devices [2,3,4,5]. They are attractive for strain engineering, for example, to create light holes [6] or to obtain high frequency electronic devices, taking advantage of an increase in electron mobility due to the decrease in effective electron mass with increasing lattice constant [7,8]. The lattice mismatch between InN and GaN is 10%, and the thickness of InGaN layers grown on GaN is limited so as to suppress strain-related defect formation [13].

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