Surface passivation approaches for silicon, germanium, and III–V semiconductors

Semiconductors are key to our modern society, enabling a myriad of fields, including electronics, photovoltaics, and photonics. The performance of semiconductor devices can be significantly hampered by defects occurring at the surfaces and interfaces of the semiconductor. As semiconductor devices continue to be scaled and nanostructuring is becoming more commonplace, such defects are increasingly becoming the limiting factor in the device performance. Surface passivation can be used to reduce the number of defects and improve device performance. However, effective surface passivation approaches and requirements can vary greatly depending on the semiconductor material and the envisioned application. In this review, we aim to bring together the separated fields of research on passivation of various semiconductor materials by drawing parallels and highlighting important differences in these fields. To this end, we focus on passivation of silicon, germanium, gallium arsenide, indium phosphide, and gallium nitride. For silicon, a high-quality interface with few defects is relatively straightforward to obtain, and the remaining defects at the surface can be further passivated by hydrogen. For germanium and III–V semiconductors, it is more challenging to form a high-quality interface, and the role of hydrogen for defect passivation is less clear. Nevertheless, similar surface passivation approaches are used for these various semiconductors, and mainly focus on interface management, involving the use of passivation layers combined with surface treatments and/or interlayers. Understanding and extending the toolbox of semiconductor surface passivation will be of great value for effective passivation of current and future semiconductor devices.