Reduced pressure silicon CVD on hemispherical substrates

• Published in: Journal of crystal growth Vol. 108; no. 1; pp. 319 - 334
• Main Authors: Gardeniers, J.G.E., Klein Douwel, C.H., Giling, L.J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.1991; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of crystal growth; physics of crystal growth; Physics; Temperature; Silicon; Crystal orientation; Experimental study; Chemical vapor deposition; Single crystal
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/0022-0248(91)90380-N

The orientation dependence of silicon crystal growth in the Si- H- Cl CVD system is studied as a function of temperature and chlorine/hydrogen ratio in the gas phase for pressures of 0.1 and 0.01 atm. This is done with the aid of hemispherical single crystal substrates. The transition from macroscopic steps at low temperatures to flat { hhk} h < k faces, viz. {113}, {337} and {771 3}, at high temperatures, as reported in an earlier paper, is reinvestigated. In accordance with the earlier study it is found that this transition is not only dependent on the chlorine/hydrogen ratio in the gas phase, but also on the pressure in the growth system. The observed trend is consistent with the idea that adsorption is responsible for the destabilization of these faces. The experimentally found pressure dependence of the transition is not as large as is predicted with the aid of the previously developed model based on Cl and/or H adsorption, however. In this paper an explanation for this discrepancy is suggested, which is based on the increasing importance of surface kinetic processes at lower pressures. As was reported before, the stability of the {001} and the { hhk} h > k faces, i.e. {331}, {551}, decreases with increasing temperature. At the lower pressures it is additionally found that the stability of these faces is lower for lower chlorine/hydrogen ratios in the gas phase; it is also lower for a lower pressure. This proves that besides thermal roughening as the main reason for the destabilization, also the decrease in the coverage of these faces, which takes place at a lower chlorine/hydrogen ratio in the gas phase or at a lower pressure in the growth system, results in less stable { hhk} h > k fac