A Bendable Microwave GaN HEMT on CVD Parylene-C Substrate

In this paper, a fabrication method of bendable gallium nitride (GaN) high-electro-mobility-transistor (HEMT) with state-of-the-art power performance is demonstrated for microwave application. Firstly, in the thinning process, a 5 µm remained silicon carbide (SiC) is used as thermal transition layer by consideration of thermal transmission. Furthermore, a 30 µm Parylene-C film deposited on the SiC substrate by using CVD method at room temperature minimize degradation due to extra strain induced in the conventional transfer process. By using the methods above, the fabricated 10 × 100 × 0.25 µm2 devices exhibited 418 mW output power at 3 GHz with a power added efficiency (PAE) over 40% at flat condition. Under the maximum 0.75% strain condition, the output power degraded less than and the PAE degraded less than 3%. The proposed fabrication methods can be used for flexible microwave GaN amplifiers in flexible wireless systems.