Homoepitaxial Regrowth of AlGaN on AlGaN Templates Prepared via Chemical Mechanical Polishing and Its Application to UV‐B Laser Diodes

Abstract

In this article, the homoepitaxial regrowth of AlGaN on AlGaN templates fabricated via chemical mechanical polishing (CMP) on periodically aligned AlN nanopillars is reported on. These templates are lattice relaxed according to X‐Ray diffraction reciprocal space mapping measurements, with a low dislocation density of ≈3 × 108 cm−2. However, the AlGaN surface has hillocks exceeding 104 cm−2. Contrastingly, no hillocks are observed on the homoepitaxially regrown AlGaN on the CMP–AlGaN template and after the UV‐B laser diode (LD) layer structure is crystallized and grown on the homoepitaxially regrown AlGaN. Furthermore, when this wafer is processed for LD fabrication, room‐temperature pulsed oscillation is confirmed in the UV‐B region at a wavelength of 296 nm. The turn‐on voltage and operating voltage also reduce by ≈2 V.