Gallium Nitride on Silicon HEMTs for Wireless Infrastructure Applications, Thermal Design and Performance

GaN HEMTs are being touted as the next generation microwave power transistor. Many research groups have reported outstanding DC and RF results on small periphery devices. However, the data on larger devices is somewhat limited. This paper will present results on large periphery devices (18 mm total gate width). Results from DC, RF and Linearity measurements will be presented. In addition a detailed thermal analysis based on simulation and measurement will be discussed. To our knowledge this is the first time the thermal characteristics of large periphery GaN -on-Si devices has been presented. Finally, the thermal model is used to study the thermal performance of these devices on different substrates. The results illustrate that GaN-on-Si is a viable approach for handling the large thermal dissipation requirements of microwave power transistors.