Flip‐chip bonding and fabrication of well‐ordered nanocolumn arrays on sputter‐deposited AlN/Si (111) substrate

Abstract

Employing a thin AlN film sputter‐deposited on Si substrates, well‐ordered GaN nanocolumn arrays were demonstrated by RF‐plasma‐assisted molecular‐beam‐epitaxy selective‐area growth. Dislocation‐free crystals were grown even on this cost‐effective framework, which included high‐density threading dislocations (>3 × 1011 cm−2), by applying nanocolumn growth techniques. Single‐peak PL spectra from integrated InGaN/GaN MQW were obtained in red region and the peak wavelength changed from 640 to 690 nm with increasing nanocolumn diameter. This framework also contributes to a fabrication of vertical injection type flip‐chip structure, even if a nanocolumn device. Damage‐free wet‐etching removal of Si substrates resulted in exposure of flip‐chip well‐ordered nanocolumns array.(a) TEM image of nanocolumns array on sputter‐deposited thin AlN film/Si (111) substrate. (b) SEM image of flip‐chip well‐ordered nanocolumns array.