Recent advances in GaN microwave HEMTs: buffer-free stack and thermal management strategies

AlGaN/GaN microwave HEMTs are a mature technology and fast penetrating the market for 5G/wireless communication and military/strategic applications. However, challenges still remain in terms of improving the management of heat which is generated in such devices. Diamond heat sink has been extensively studied for this although commercial RF HEMTs still use Cu-heat sink. In this talk, we shall show our recent results on developing a cooling manifold using microfluidic channels whereby laser is used to etch the channels. The superiority of this approach against usual DRIE-etch based approach will be discussed along with experimental results. Our ongoing work on multi-finger X-band HEMTs with such liquid-cooling approach will be presented. <br/>In the next part, we shall discuss our recent results on buffer-free GaN HEMTs with respect to C- and X-band performance, The study on passivation, gate dielectric and development of multi-finger HEMTs on such platforms will be presented along with load pull data.