Dependence of GaN HEMT Millimeter-Wave Performance on Temperature

This paper presents extensive thermal characterization of recently fabricated high-performance millimeter-wave GaN/SiC devices from four sources across temperature (-25??C to + 125??C). The changes with temperature for: output power at millimeter-wave frequencies (P_out), pinchoff voltage (V_p), knee-voltage (V_k), onresistance (R_on), power-added efficiency (PAE), saturated drain current (I_dss), power gain (G), and transconductance (g_m) are measured, statistics studied, and correlations investigated. Temperature-coefficients are established for P_out, V_p, V_k, R_on, PAE, I_dss, G, and g_m in GaN technology. The main findings are: 1) P_out´s temperature dependence can be negative or positive, opposite of G´s and I_dss´s strong negative temperature dependence, and 2) the pinchoff voltage´s dependence on temperature is very weak. The results obtained provide monolithic microwave integrated circuit designers with key information required for meeting performance over a wide temperature range.