J. Phys. IV France 02 (1991) C2-63-C2-70
SILICON DEPOSITION FROM DISILANE : EXPERIMENTAL STUDY AND MODELLINGM. GUEYE1, E. SCHEID2, P. TAURINES2, P. DUVERNEUIL1, D. BIELLE-DASPET2 and J.P. COUDERC1
1 Laboratoire de Génie Chimique, URA 192 du CNRS, ENSIGC, Chemin de la Loge F-31078 Toulouse cedex, France
2 UPR 8001 du CNRS, LAAS, 7, avenue du Colonel-Roche, F-31077 Toulouse cedex, France
Undoped silicon films have been deposited from disilane in a tubular hot wall LPCVD reactor and their physical properties have been analyzed. A two dimensional model taking into account a detailed gas phase chemical mechanism has been developed to simulate the growth rate distribution on a wafer. The numerical predictions have been compared with experimental results and a good agreement has been found in various conditions of temperature and pressure. This work has demonstrated that the main contribution to silicon deposition involves the radical silylene in the case of disilane, whereas in the case of silane as a gaseous source it involves silane itself, so suggesting a possible explanation for the very important differences observed in crystalline characteristics of silicon layers. From a more practical point of view, the much larger size of crystals obtained when starting from disilane opens interesting possibilities of industrial developments, in particular for the manufacture of thin film transistors.
© EDP Sciences 1991