AlN epitaxial growth on off-angle R-plane sapphire substrates by MOCVD

Effect of c‐plane sapphire misorientation on the growth of AlN by high‐temperature MOVPE

“…Therefore, misoriented sapphire is also promising as a substrate for growing high-quality AlN with an atomically flat surface. Shibata et al reported the effect of the misorientation of r-plane sapphire on the crystalline quality of AlN [7]. However, to date, there are few reports concerning the effect of sapphire misorientation from the (0001) plane on the crystalline quality and surface flatness of AlN [8].…”

High-sensitivity, wide-dynamic-range avalanche photodiode pixel design for large-scale imaging arrays

“…The wide bandgap semiconductor material aluminum nitride ͑AlN͒ is closely lattice matched and refractive index matched to both sapphire and silicon, and offers the prospect of enabling fabrication of high transmittance ͑100͒ silicon-on-͑AlN͒-sapphire substrates for backilluminated silicon imagers. [8][9][10] The APD in Fig. 1 has been designed for wide dynamic range operation by allowing the polysilicon cathode to extend beyond the edges of the mesa top over the thermally grown passivation oxide to form an MOS capacitor that acts as a charge-coupled device ͑CCD͒ gate.…”

a ‐plane AlN and AlGaN growth on r ‐plane sapphire by MOVPE

“…With the exception of when the off-angle was between -1 o and +1 o , the RMS roughness improved with decreasing magnitude of the off-angle. Although an off-angle of -4 o for sapphire has been reported to be suitable for the growth of a-plane AlN [1], the crystalline quality of a-plane AlN on r-plane sapphire with an off-angle between -1 o and 1 o was better than that for larger off-angles. When the off-angle of r-plane sapphire is larger than 2 o or smaller than -2 o , it is suggested that nuclei do not form sequentially from the atomic step.…”

“…In recent years, intense research on nonpolar AlN and AlGaN has been performed with the aim of application to LEDs and LDs in the deep ultra-violet (UV) region [1][2][3][4]. However, while LEDs based on c-plane AlN with a wavelength of 210 nm have been commercially realized [5], in the case of LEDs using nonpolar AlN, only wavelengths of up to 363 nm have been reported [6].…”

“…For the growth of a-plane AlN, we examined the dependence of the crystallinity and surface morphology on the underlying layer, V/III ratio (92-921), growth temperature (1200-1430 o C) and the off-angle of r-plane sapphire. Here, the sign of the angle is denoted as plus when the angle between the c-plane and the surface of the sapphire substrate is greater than that between the rplane and the c-plane [1,13,14]. When the abovementioned angle is less than the angle between the r-plane and the c-plane, it is indicated as minus.…”