Papers by Author: D. Panknin

Abstract: The epitaxial relationship of Si deposited on 3C-SiC was studied using both free standing 3C-SiC(100) material from Hoya and 3C-SiC thin layers deposited on Si(100) as substrates. The conditions of Si growth were varied depending on the substrate. When Si is deposited at 1000°C on (001) 3C-SiC, it is in perfect epitaxial relation with the SiC layer [100]Si//[100]SiC and [001]Si//[001]SiC. After a 20 ms flash lamp pulse on the same sample, which has the effect of fast melting of the Si top layer only, the defects in the Si are eliminated. Using free standing 3C-SiC, the deposition temperature was not limited by the Si melting point so that it was fixed at 1500°C in order to form a set of Si liquid droplets on the surface with diameters ranging from 5 to 20 μm. Surprisingly more than 60% of the Si droplets exhibit the epitaxial relation [110]Si//[001]SiC and [111]Si//[110]SiC after crystallization. The occurrence of this epitaxial relationship can be understood in terms of lattice mismatch reduction from 20% to 18.3%. The conditions of crystallization, most probably the cooling rate, seem to have a strong effect on Si orientation.

Abstract: Flash lamp annealing of multilayer stack of the type SiC/Silicon overlayer(SOL)/SiC reduces the defect densities in the 3C-SiC/Si heteroepitaxial structure. Ge and C additions to the SOL lead to a substantial increase of the mass transfer from the upper layer to the lower SiC layer. If the Ge content of the SOL and the flash lamp annealing conditions are properly chosen a homogeneous layer with a 3C-SiC thickness between 150 and 200 nm can be achieved corresponding to a growth rate between 7.5 and 10.0 +m/s. The thickening of the lower layer depends on the SOL composition. Ge and/or C incorporation into the SOL and therefore into the Si melt enhances the mass transport from the upper SiC layer to the lower one.

Abstract: An approach for the defect density reduction in 3C-SiC epitaxially grown on Si is to improve the quality of the carbonized layer during the early stage of growth. For this reason the conventional carbonization process was replaced by a slower and nearer equilibrium carbonization method. Carbon is introduced by implantation into oxide of an oxidized Si substrate, near the SiO2/Si interface, and then it is transferred to the Si surface by annealing. Good quality 3C-SiC grains are formed embedded into the Si substrate, which are absolutely flat at the SiO2/Si interface. Another advantage of the new carbonization process is the elimination of the cavities due to the suppression of Si out-diffusion.

Abstract: The influence of the different additions to the melt on the nucleation behavior during short time flash lamp processing was investigated. It was observed that germanium and carbon additions to the silicone melt led to an increase of the mass transport to the growing surface and to an increase of the nuclei size. In the case of germanium additions to the silicon melt an incorporation of germanium in the silicon substrate was observed.

Abstract: Thin 3C-SiC films epitaxially grown on Si-substrate are substantially improved by the FLASIC process, which involves irradiation with flash lamps with pulse duration of 20ms. The disadvantages of the standard FLASIC process are the undulations introduced in the SiC film due to melting of the Si-substrate and the Si mass transport near the SiC/Si interface during the flash. An improved structure was realised in order to minimize the undulations of the SiC, improving also the quality of the film. This structure involves the deposition of a silicon overlayer (SOL) on the initial SiC layer, followed by an additional SiC capping layer acting as a source for SiC transfer by liquid phase epitaxy to the lower SiC layer. Significant mass SiC transport from the upper to the lower SiC layer through the SOL occurs during the flash. The new structure is characterized as inverse - FLASiC. The structural characteristics of the new structure were studied by transmission electron microscopy and atomic force microscopy.