Device performance of p-Ge MOSFETs at liquid nitrogen temperature

The device performance of p-channel Ge MOSFETs at liquid nitrogen temperature is reported and initial results of room temperature irradiation with 2-MeV electrons on the cryogenic device performance is described. It is shown that at 77 K an increase of the drain current and gm is observed. This increase of the gm can be explained by considering the balance between reduced phonon scattering on the one hand and increased Coulomb scattering by interface states, on the other. After irradiation, a slight negative shift of the threshold voltage and a decrease of the drain current for input and output characteristics have been observed together with a decrease of the transconductance (gm).