Author(s): Cai, TS (Cai, Tingsong); Guo, YA (Guo, Yanan); Liu, ZB (Liu, Zhibin); Zhang, RJ (Zhang, Ruijie); Wang, DD (Wang, Dadi); Liu, NX (Liu, Naixin); Yi, XY (Yi, Xiaoyan); Li, JM (Li, Jinmin); Wang, JX (Wang, Junxi); Yan, JC (Yan, Jianchang)
Source: SEMICONDUCTOR SCIENCE AND TECHNOLOGY Volume: 38 Issue: 6 Article Number: 064002 DOI: 10.1088/1361-6641/acd021 Published: JUN 1 2023
Abstract: Preparing high quality non-polar aluminum nitride (AlN) templates is the key to improving the performance of non-polar deep-ultraviolet light-emitting diodes. In this study, we investigated the effect of buffer layer on the crystallinity and surface morphology of a-plane AlN films regrown by pulsed-flow mode (PM) metal-organic vapor phase epitaxy (MOVPE). Three buffer layers were compared including low-temperature AlN buffer layer grown by MOVPE (MO-buffer), sputtered AlN buffer layer (SP-buffer), and high-temperature annealed sputtered AlN buffer layer (HTA-buffer). It is found that the (11-20) plane x-ray rocking curve-full width at half maximum (XRC-FWHM) values of a-plane AlN films are significantly reduced after the regrowth process. Thanks to the high crystalline quality of HTA-buffer, AlN regrown on HTA-buffer exhibits the smallest (11-20) plane XRC-FWHM values of 1260/1440 arcsec along the [0001]/[1-100] direction. The mosaic tilt and basal plane stacking fault density are estimated to be 0.41. and 1.76 x 106 cm(-1), respectively. The surface shows a uniform stripe-like pattern with the lowest root mean square value of 0.82 nm. Furthermore, the a-plane AlN epilayer regrown on HTA-buffer displays a weak in-plane stress anisotropy and high optical transmittance in the ultraviolet-visible region. Our work suggests that combining the PM regrowth with HTA-AlN buffer layer is a promising route to prepare high-quality a-plane AlN templates for efficient non-polar deep-ultraviolet light emitters.
Accession Number: WOS:000981875500001
ISSN: 0268-1242
eISSN: 1361-6641