Substantially facet-free selective epitaxial growth process
AssigneeAT&T Bell Laboratories
InventorsAnatoly Feyenson, John W. Osenbach, Donald G. Schimmel
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Abstract
A process for growing selective epitaxial layers on a silicon substrate. In a epitaxial growth reactor, hydrogen and the reactive gasses, the silicon source gas and hydrochloric acid, are introduced. The amount of silicon to free hydrochloric acid is controlled to be about 1:6 during the growth process and then turned off, the hydrogen remaining on. The resulting epitaxial layer may be grown over one micron in thickness with less than 0.1 micron of faceting. Further, a etchant of H.sub.2 O and HF diluted in NHO.sub.3 is first used to remove surface damage on the silicon substrate prior to epitaxial layer growth.
Claims7
A method of growing epitaxial layers on selected portions of at least one silicon substrate, the substrate covered with a masking layer having openings therein to expose said portion of the substrate where an epitaxial layer is to be grown, characterized by the step of:
- flowing hydrogen, hydrochloric acid (HCl), and a silicon source gas (SiCl.sub.x H.sub.y, 2.ltoreq.x.ltoreq.4, 0.ltoreq.y.ltoreq.2) over the substrate at predetermined flow rates;
- wherein the temperature of the gases and substrate is at least about 900.degree. C. and less than about 1100.degree. C., the flow rate of the hydrogen at least about 15 SLM and no more than about 180 SLM, the flow rate of the silicon source gas is at least about 50 SCCM and no more than about 150 SCCM, the flow rate of the hydrochloric acid ranges from at least 200 SCCM to no more than 420 SCCM, the pressure in the reactor is less than about 60 Torr;
- and
- wherein the ratio of silicon atoms to free HCl molecules ranges from about 1:5 to about 1:8.
Dependencies are inferred from the claim text.