Si1−xGex (x≥0.2) crystal growth in the absence of a crucible

Abstract

In this work we made a first attempt to grow Si1−xGex single crystals by the so called modified float zone technique [1], without contact of container walls, using a modified AHP (axial heat flux close to the phase interface) heater. This method was derived from the “modified Bridgman” technique using a submerged heater [2]. Some advantages of this method are the improvement in crystal quality [3,4], the reduction of the radial temperature gradient and with it the reduced radial segregation during the growth experiment. For comparison another Si1−xGex crystal was grown by the conventional float zone method, using a residual spark plasma sintered feed rod from the initially described growth experiment. Spark plasma sintering is a synthesis and consolidation technique using a pulsed current and an axial pressure to activate the sintering process [5]. Both samples were characterized by EDX, ICM, Raman and Photoluminescence spectroscopy for the purpose of analyzing the crystal quality. The use of spark plasma sintered raw material as feed material was investigated.