Disilane doping of semi-polar (11-22) n-GaN: The impact of terrace-like evolution toward the enhancement of the electrical properties

Abstract

Semi-polar (11-22) n-type gallium nitride thin films with various disilane doping levels were deposited via metal-organic chemical vapor deposition. The impact of the dissimilar disilane doping levels on the crystal, morphological, strain, and electrical properties was extensively studied. An X-ray rocking curve analysis demonstrated an improved crystal quality with enhanced terrace-like features using 15 standard cubic centimeters per minute of disilane doping. A closely packed step terrace-like feature was exhibited, reducing the density of arrowhead-like features. This facilitated a smoother surface with a root mean square surface roughness of 5.7 nm. Raman spectroscopy revealed that using an intermediate disilane flux reduced the compressive strain. An electrical analysis also showed that a moderate disilane doping level improved the carrier concentration and mobility to 1.3 × 1018 cm−3 and 99.3 cm2. V−1. s−1, respectively.