High field drift velocity of 2DEG in Si/SiGe heterostructures as determined by magnetoresistance techniques

Recently Si/SiGe n-MODFETs with transconductances exceeding 300 mS/mm at 300K and 600 mS/mm at 77K have been demonstrated. Accurate modelling of these short channel devices (L<1 /spl mu/m) requires knowledge of hot electron drift velocities as a function of the electric field. Many theoretical calculations have been done to determine these dependences. We present here the first experimental determination of the high field drift velocity of 2DEG in Si/SiGe n-type modulation doped structures at 10K and 77K for fields varying from 0.1 V/cm to 3000 V/cm by magnetoresistance measurements. The samples are n-type modulation doped single quantum wells grown by RTCVD. They consist of a modulation doped 75 /spl Aring/ strained Si quantum well on a relaxed graded SiGe buffer layer.