Design Rules for Addressing Material Asymmetry Induced by Templated Epitaxy for Integrated Heteroepitaxial On‐Chip Light Sources

Integrating quantum dot (QD) gain elements onto Si photonic platforms via direct epitaxial growth is the ultimate solution for realizing on‐chip light sources. Tremendous improvements in device performance and reliability have been demonstrated in devices grown on planar Si substrates in the last few years. Recently, electrically pumped QD lasers deposited in narrow oxide pockets in a butt‐coupled configuration and on‐chip coupling have been realized on patterned Si photonic wafers. However, the device yield and reliability, which ultimately determines the scalability of such technology, are limited by material uniformity. Here, detailed analysis is performed, both experimentally and theoretically, on the material asymmetry induced by the pocket geometry and provides unambiguous evidence suggesting that all pockets should be aligned to the [1 1¯0$\bar{1}\ 0$] direction of the III‐V crystal for high yield, high performance, and scalable on‐chip light sources at 300 mm scale. Monolithic integration of III‐V quantum dot (QD) lasers on Si photonic wafers in narrow pockets in a butt‐coupled configuration via direct epitaxy is the ultimate solution for achieving on‐chip light sources. The pocket orientation dependence of QD quality and the pocket geometry dependence of stress and defect configuration have been investigated experimentally and theoretically. This study offers guidance to obtain integration templates that will facilitate high yield and high performance epitaxial on‐chip lasers at large scale.