STRUCTURAL AND ELECTRICAL-TRANSPORT PROPERTIES OF EXCIMER (ARF)-LASER-CRYSTALLIZED SILICON-CARBIDE

The structural and electrical properties of undoped and doped microcry stalline silicon carbide (mu c-SiC) thin films prepared by excimer (Ar F) laser crystallization of plasma-enhanced chemical vapour deposited hydrogenated amorphous silicon carbide (a-SiC:H) have been analysed. U sing transmission electron microscopy this material is shown to posses s partial beta-SiC structure. Bonding configurations have also been ch aracterized by infrared spectroscopy. It is shown that a-SiC:H films h aving a carbon content as large as 30 at.% can be crystallized by this novel method. After crystallization, all films show greater than six orders of magnitude increase in dark conductivity sigma(dc). The tempe rature dependences of sigma(dc) for undoped, n- and p-type mu c-SiC ex hibit different characteristic shapes. For all samples, it is shown th at the increase in sigma(dc) is not predominantly due to the activatio n of dopant atoms. Instead, the change is associated with the formatio n of a microcrystalline structure. However, dopant sites, but not carb on content (up to 30 at.%), play an important role in electrical trans port in mu c-SiC.