Microwave noise performance and modeling of SiGe-based HFETs

Microwave noise performance of SiGe-based heterostructure field effect transistors (HFETs) is presented. Noise parameters for devices with buried channel fabricated on several virtual substrates are discussed. The impact of such strain relieved buffers on device noise performance is estimated by a proper noise de-embedding technique. Then, the noise properties measured in the 2.5-18-GHz frequency range are compared with those of other technologies. Noise parameters of SiGe HFETs are simulated using Pospieszalski´s and Van Der Ziel´s noise models. Some detrimental effects like access resistances and self-heating effects that negatively impact the microwave noise behavior are discussed and some alternatives to overwhelm them are proposed.