Microstructure and enhanced morphology of planar nonpolar m-plane GaN grown by hydride vapor phase epitaxy |
| |
Authors: | Benjamin A Haskell Arpan Chakraborty Feng Wu Hideo Sasano Paul T Fini Steven P Denbaars James S Speck Shuji Nakamura |
| |
Affiliation: | (1) Materials Department, University of California, 93106 Santa Barbara, CA;(2) NICP/ERATO JST, UCSB Group, University of California, Santa Barbara;(3) Japan Patent Office, 100-8915 Tokyo, Japan |
| |
Abstract: | Nonpolar (
) m-plane gallium nitride has been grown heteroepitaxially on (100) γ-LiAlO2 by several groups. Previous attempts to grow m-plane GaN by hydride vapor phase epitaxy (HVPE) yielded films unsuitable for
subsequent device regrowth because of the high densities of faceted voids intersecting the films’ free surfaces. We report
here on the growth of planar m-plane GaN films on (100) γ-LiAlO2 and elimination of bulk and surface defects. The morphology achieved is smooth enough to allow for fabrication of m-plane
GaN templates and free-standing substrates for nonpolar device regrowth. The GaN films were grown in a horizontal HVPE reactor
at 860–890°C. Growth rates ranged from 30 μm/h to 240 μm/h, yielding free-standing films up to 250-μm thickness. The m-plane
GaN films were optically specular and mirror-like, with undulations having 50–200-nm peak-to-valley heights over millimeter
length scales. Atomic force microscopy revealed a striated surface morphology, similar to that observed in m-plane GaN films
grown by molecular beam epitaxy (MBE). Root-mean-square (RMS) roughness was 0.636 nm over 25-μm2 areas. Transmission electron microscopy (TEM) was performed on the m-plane GaN films to quantify microstructural defect densities.
Basal-plane stacking faults of 1×105 cm−1 were observed, while 4×109 cm−2 threading dislocations were observed in the g=0002 diffraction condition. |
| |
Keywords: | Nonpolar GaN hydride vapor phase epitaxy (HVPE) transmission electron microscopy (TEM) surface morphology |
本文献已被 SpringerLink 等数据库收录! |
|