Temperature induced substrate effect in monolithic RF active and passive devices on silicon

In this paper, we demonstrate analyses of the effects of temperature (from -50°C to 200°C) on the power gain performance of RF active devices (MOSFETs and SiGe HBTs) and on the noise figure (NF) performance of RF passive devices (inductors and transformers) for the first time. For RF active devices, it was found that the maximum stable power gain/maximum available power gain (G_ms/G_Amax) and the square of the short-circuit current gain, (|H₂₁|²) decrease with increasing temperature but show a reverse behavior within a higher frequency range. This phenomenon can be explained by the negative temperature coefficient of the transconductance (g_m) and the positive temperature coefficient of the substrate resistance (R_sub). For RF passive devices, it was found that the NF increases with increasing temperature but show a reverse behavior within a higher frequency range. This phenomenon can be explained by the positive temperature coefficients of the metal series resistance (R_s) and the substrate impedance (Z_sub). The present analyses are helpful for RF engineers to design less temperature-sensitive RF active and passive devices, and consequently for radio- frequency integrated circuits (RF-ICs).