Compliant Micron-Sized Patterned InGaN Pseudo-Substrates Utilizing Porous GaN

Shubhra S Pasayat; Chirag Gupta; Yifan Wang; Steven P DenBaars; Shuji Nakamura; Stacia Keller; Umesh K Mishra

doi:10.3390/ma13010213

Compliant Micron-Sized Patterned InGaN Pseudo-Substrates Utilizing Porous GaN

Materials (Basel). 2020 Jan 4;13(1):213. doi: 10.3390/ma13010213.

Authors

Shubhra S Pasayat¹, Chirag Gupta¹, Yifan Wang², Steven P DenBaars^{1

3}, Shuji Nakamura^{1

3}, Stacia Keller¹, Umesh K Mishra¹

Affiliations

¹ Department of Electrical and Computer Engineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
² Department of Physics, University of California, Santa Barbara, CA 93106, USA.
³ Materials Department, University of California, Santa Barbara, CA 93106, USA.

Abstract

The compliant behavior of densely packed 10 × 10 µm² square patterned InGaN layers on top of porous GaN is demonstrated. The elastic relaxation of the InGaN layers is enabled by the low stiffness of the porous GaN under layer. High resolution X-ray diffraction measurements show that upon InGaN re-growths on these InGaN-on-porous GaN pseudo-substrates, not only was the regrown layer partially relaxed, but the degree of relaxation of the InGaN pseudo-substrate layer on top of the porous GaN also showed an increase in the a-lattice constant. Furthermore, methods to improve the surface morphology of the InGaN layers grown by metal-organic chemical vapor deposition (MOCVD) were explored in order to fabricate InGaN pseudo-substrates for future optoelectronic and electronic devices. The largest a-lattice constant demonstrated in this study using this improved method was 3.209 Å, corresponding to a fully relaxed InGaN film with an indium composition of 0.056.

Keywords: MOCVD; compliant pseudo-substrate; composition pulling effect; gallium nitride; indium gallium nitride; porous GaN; relaxed InGaN pseudo- substrate.

Grants and funding

N00014-17-1-2106/Office of Naval Research