Publication
Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Conference paper

Atomic layer epitaxy of silicon by dichlorosilane studied with core level spectroscopy

View publication

Abstract

The chemisorption and reaction of dichlorosilane (SiH2Cl2 with Si(111) and Si( 100) surfaces is investigated with core-level soft x-ray photoelectron spectroscopy employing synchrotron radiation, in order to ascertain the surface chemistry involved in atomic layer epitaxy (ALE). Exposures to 8 kL of SiH2Cl2 were performed as a function of sample temperature in the range from room temperature to 800 °C. At all temperatures, SiH2Cl2 chemisorbs dissociatively forming silicon monochloride surface species. The coverage of monochloride displays a maximum for exposures at —600 °C. Under all conditions studied, larger chlorine coverages are observed on Si(100) than on Si(lll). A Si surface that was first saturated with SiH2Cl2 at 600 °C was subsequently exposed to H2 at 600 °C, and no reaction occurred. These results indicate that recent models for silicon ALE are incorrect. An alternative method for low-temperature ALE of Si is proposed, in which SiH2Cl2 is adsorbed onto Si at 600 °C and Cl is removed via reaction with atomic H. © 1992, American Vacuum Society. All rights reserved.