Thermal resistance optimization of GaN-on-Si materials for RF HEMTs based on structure function method and static-pulsed I–V measurements

A major obstacle in the commercialization of GaN-on-Si RF HEMTs lies in the elevated thermal resistance introduced by the AlN/AlGaN multi-layer buffer, employed for stress management. This issue adversely impacts device performance and reliability. In this study, the structure function method was utilized to precisely determine the intrinsic thermal resistance of GaN-on-Si materials. Results reveal that a single-layer AlN buffer demonstrates a significantly enhanced heat dissipation capability compared to conventional AlN/AlGaN multi-layer or superlattice buffer. Additionally, the thermal performance of device under operation was quantitatively assessed using static-pulsed I–V measurements. Through theoretical simulations, the influence of GaN buffer structures on heat distribution within GaN-on-Si RF devices was explored, indicating that optimizing GaN buffer thickness can further enhance thermal performance. This research offers a thorough understanding of the relationship between material structures and RF device thermal behavior, providing crucial insights for the thermal management design of GaN-on-Si RF HEMTs.