GROWTH OF 4H-SIC FROM LIQUID-PHASE

Epitaxial layers of 4H-SiC have been grown from a carbon saturated Si- Sc melt in the range of 1700-1850 degrees C. The growth process has be en evaluated concerning the growth rate, liquid zone stability, surfac e morphology, structural quality and polytype reproducibility. Growth rates exceeding 300 mu m h(-1) have been achieved. From the temperatur e dependence of the growth rate the apparent activation energy of the growth process has been calculated. The growth rate is found to be dep endent on the condition of the liquid zone. The morphology of the laye rs varies with the growth process which changes after the initial grow th stage. The morphology is getting rougher with increasing layer thic kness and is also affected by the dissolving interface. The substrate polytype is reproduced at the composition of the Si-Sc melt used. The conditions for constitutional supercooling of the liquid solution are discussed. The layers have been characterized by optical microscopy, S IMS, low-temperature photoluminescence, Raman scattering and X-ray dif fraction (XRD) techniques. (C) 1997 Elsevier Science S.A.