AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP24
P Incorporation during Si(001):P Gas-Source Molecular Beam Epitaxy: Effects on Growth Kinetics and Surface Morphology

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: B. Cho, University of Illinois at Urbana-Champaign
Authors: B. Cho, University of Illinois at Urbana-Champaign
J. Bareno, University of Illinois at Urbana-Champaign
Y.L. Foo, Institute of Materials Research and Engineering, Singapore
S. Hong, Seoul National University, Korea
T. Spila, University of Illinois at Urbana-Champaign
I. Petrov, University of Illinois at Urbana-Champaign
J.E. Greene, University of Illinois at Urbana-Champaign
Correspondent: Click to Email
The effects of P doping on growth kinetics and surface morphological evolution during Si(001):P GS-MBE from Si@sub2@H@sub6@ and PH@sub3@ at temperatures T@subs@ = 500-900 °C have been investigated. With increasing PH@sub3@/Si@sub2@H@sub6@ flux ratio J@subP/Si@ at constant T@subs@, we observe a decrease in the film growth rate R, accompanied by increased surface roughening and pit formation. At constant J@subP/Si@, R increases with increasing T@subs@, while the incorporated P concentration C@subP@ initially increases, reaches a maximum at T@subs@ = 700 °C, and then decreases at higher growth temperatures. We use in-situ D@sub2@ temperature programmed desorption (TPD) to follow changes in film surface composition and dangling bond density @theta@@subdb@ as a function of J@subP/Si@ and T@subs@. Measurements on both as-deposited Si(001):P layers and P-adsorbed Si(001) reveal @beta@@sub1@ and @beta@@sub2@ peaks due to D@sub2@ desorption from Si monohydride and dihydride species, respectively, as well as the formation of a third peak @beta@@sub3@ corresponding to D@sub2@ desorption from mixed Si-P dimers. Dissociative PH@sub3@ adsorption on Si(001) results in a decrease in @theta@@subdb@ and an initial increase in P surface coverage @theta@@subP@ with increasing T@subs@. @theta@@subP@ reaches a maximum value of 0.95 ML at T@subs@ = 550 °C, and decreases with T@subs@ > 600 °C due to the onset of P@sub2@ desorption. Comparison of @theta@@subP@(T@subs@) with C@subP@(T@subs@) results obtained during film growth reveals the presence of strong P surface segregation. From measurements of @theta@@subP@ vs. C@subP@ in Si(001):P layers, we obtain a P segregation enthalpy @DELTA@H@subs@= -0.86 eV. Using the combined set of results, we develop a predictive model for C@subP@ vs. T@subs@ and J@subP/Si@, incorporating the dependence of the PH@sub3@ sticking probability S@subPH3@ on @theta@@subP@, which provides an excellent fit to the experimental data.