Si0.5Ge0.5 bulk single crystals with uniform composition

Abstract

Compositionally uniform 10mm diameter Si0.5Ge0.5 bulk crystals were grown by the traveling liquidus-zone (TLZ) method which we developed for the alloy crystal growth. Axial compositional variation was less than 0.5at% for the length of 12mm and radial one was less than 0.3at% and showed excellent compositional uniformity. The average full width at half maximum of X-ray rocking curves for 004 diffraction measured across a disk is less than 36arcsec (0.01°) at a distance of 3.5mm away from the seed/crystal interface. This shows high crystallinity and promise of TLZ-grown crystals as substrates for CMOS devices using n-channels of strained Si thin films and p-channels of strained Ge thin films.