RF performance and microwave noise of metamorphic InP/InGaAs heterojunction bipolar transistors at elevated temperature

A detailed characterization of RF and microwave noise performance of metamorphic InP/InGaAs/InP DHBTs in the temperature range of 300 K to 380 K is performed, and the differences between the MHBT and the referenced lattice-matched InP DHBT are compared. The experimental results show that, in the temperature range of 300 to 380 K, the f_t and f_max for both MHBT and LHBT decrease with the increase in temperature. Slightly higher percentage of degradation is observed for the MHBT that may probably be due to the higher thermal resistance of the metamorphic buffer and the GaAs substrate. Similar to the RF characteristics, the MHBT shows a slightly larger variation of NF_min compared to LHBT. However, results suggest that, even though the MHBT may have much higher thermal resistance, this may not significantly affect the device RF characteristics and microwave noise performance.