High-Quality 2$''$ Bulk-Like Free-Standing GaN Grown by HydrideVapour Phase Epitaxy on a Si-doped Metal Organic Vapour Phase Epitaxial GaN Template with an Ultra Low Dislocation Density

概要

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High-quality 2$''$ crack-free free-standing GaN has been attained by hydride vapour phase epitaxial growth on a Si-doped MOVPE GaN template with a low dislocation density and subsequent laser-induced lift-off process. A low value of dislocation density of ${\sim}2.0\times 10^{7}$ cm-2 on the Ga-polar face was determined from cathodoluminescence images. X-ray diffraction (XRD) and low-temperature photoluminescence (PL) were exploited to investigate the structural and optical properties of the GaN material. The full width at half maximum value of XRD $\omega$-scan of the free-standing GaN is 248 arcsec for the ($1\ 0\ \bar{1}\ 4$) reflection. The XRD and low-temperature PL mapping measurements consistently proved the high crystalline quality as well as the lateral homogeneity and the small residual stress of the material. Hence, the bulk-like free-standing GaN studied here is highly advantageous for being used as a lattice-constant and thermal-expansion-coefficient matched substrate for additional strain-free homoepitaxy of III–nitrides-based device heterostructures. The strain-free homoepitaxy will significantly reduce the defect density and thus, an improvement of the device performance and lifetime could be achieved.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2005-03-15