Depletion mode MISFETs have been fabricated and operated on long wavelength (λ
c= 11.0 µm) Hg
1-xcd
xTe for the first time. Current voltage characteristics of the devices are presented and discussed. The surface mobility of electrons has been calculated from these data to be

cm
2/Vs the highest ever observed on a Hg
1-xCd
xTe to MISFET. Small signal parameters are also derived from current voltage characteristics. The operation of a Hg
1-xcd
xTe MISFET as an amplifier with gain is demonstrated, and data on a fully integrated Hg
1-xcd
xTe source follower circuit is presented and discussed.