Substrate removal of AlGaN/GaN HEMTs using laser lift‐off

AlGaN/GaN high electron mobility transistors are very promising for microwave power applications. Integration and packaging of those high power density devices requires specific attention to thermal management, especially when the AlGaN/GaN heterostructures are grown on sapphire substrates. Indeed, the low thermal conductivity of sapphire is limiting the power performance of the devices. To improve the thermal management, we propose to remove the sapphire substrate after the HEMT processing. In this paper we show that the sapphire substrate can be removed using laser lift-off, without any substantial degradation of the HEMT properties. This is a first important step towards a system-in-a-package integration of AlGaN/GaN HEMTs for RF power applications. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)