Epitaxial lift-off for III-nitride devices

Abstract

Abstract Epitaxial lift-off (ELO) is a process technology used to separate thin semiconductor layers from their original epitaxial growth substrate in order to transfer these layers to a new substrate with improved performance. Group-III nitride materials are deposited on a diverse range of substrates that include non-native materials such as sapphire, SiC and silicon, as well as more recently available, high-quality bulk GaN substrates that enable homoepitaxial growth. Gallium nitride materials support a multitude of device technologies that span optoelectronics, high-power RF devices and power electronics. In almost all cases, nitride device performance characteristics can be enhanced through layer transfer of the devices to a new substrate with enhanced thermal, electrical, mechanical or optical properties. This chapter provides a high-level overview of the benefits of and different methods used for GaN epitaxial lift-off. This is followed by a discussion of recently developed chemical lift-off methods using pseudomorphic release layers and applications for emerging vertical GaN power electronic devices technologies on native GaN substrates.