Combined Effects of Total Ionizing Dose and Temperature on a K-Band Quadrature LC-Tank VCO in a 32 nm CMOS SOI Technology

A 20.4 GHz VCO with a tuning range of 610 MHz (3%) was designed and fabricated in a 32 nm CMOS silicon-on-insulator technology. At 36°C, the VCO achieves an output power of 0.1 dBm and a phase noise of -99 dBc/Hz at 1 MHz offset from the center frequency. TID experiments on the VCO operating at 36°C, 75°C, and 100°C show degradation in frequency, output power, and phase noise. At 100°C and 500 krad(SiO
₂
), the VCO shows a worst-case degradation of 630 MHz, 4.3 dBm, and 6.1 dBc/Hz in center frequency, output power, and phase noise, respectively. At 36°C and up to 500 krad(SiO
₂
), the VCO can be retuned to operate at the required center frequency of 20.4 GHz. However, at 100 °C, the combined effects of temperature and TID result in specification failure. The system-level impact of TID-induced degradation on VCO performance is discussed using a phase-locked loop (PLL) as an example application. Measured performance corroborates previous predictions and highlights the importance of combined effects testing for advanced RF design characterization and qualification.