AVS 47th International Symposium
    Semiconductors Monday Sessions
       Session SC+EL+SS-MoA

Paper SC+EL+SS-MoA2
Si(001):As Gas-source Molecular Beam Epitaxy: As Incorporation and Film Growth Kinetics

Monday, October 2, 2000, 2:20 pm, Room 306

Session: Reactions on Semiconductors
Presenter: H. Kim, University of Illinois
Authors: H. Kim, University of Illinois
G. Glass, PTD, Intel Corp.
J.A.N.T. Soares, University of Illinois
P. Desjardins, Ecole Polytechnique de Montreal
J.E. Greene, University of Illinois
Correspondent: Click to Email
Arsenic-doped Si(001) layers with concentrations C@sub As@ up to 5x10@super 18@ cm@super -3@ were grown on Si(001)2x1 at temperatures T@sub s@ = 575 - 900 °C by GS-MBE using Si@sub 2@H@sub 6@ and AsH@sub 3@. At constant flux ratio, C@sub As@ decreases, while the film growth rate R@sub Si:As@ increases, with T@sub s@. TPD measurements show that As segregates strongly to the growth surface and that the observed decrease in C@sub As@ at high T@sub s@ is primarily due to increasingly rapid arsenic desorption from the segregated layer. Decreasing T@sub s@ enhances As incorporation. However, it also results in lower R@sub Si:As@ due to higher steady-state As surface coverages which decrease the total dangling bond coverage and, hence, the Si@sub 2@H@sub 6@ adsorption rate. At constant T@sub s@, C@sub As@ increases, while R@sub Si:As@ decreases, with increasing AsH@sub 3@ flux. All incorporated As resides at substitutional electrically active sites for concentrations up to 3x10@super 18@ cm@super -3@, the highest value yet reported for Si(001):As growth from hydride source gases. D@sub 2@ TPD spectra exhibit @beta@@sub 1@ and @beta@@sub 2@ peaks associated with Si monodeuteride and dideuteride desorption as well as a new peak @beta@@sub 3@ attributed to desorption from Si-As mixed dimers. Steady-state arsenic surface coverages during film growth, and the As segregation enthalphy, were quantitatively determined as a function of C@sub As@ by comparison with As-adsorbed Si(001) reference samples with known As coverages. From AsH@sub 3@ adsorption kinetics and incorporation data, the AsH@sub 3@ reactive sticking probability on Si(001) was determined and As incorporation kinetics were quantitatively modeled. Initial experiments have demonstrated that temperature-modulated growth can be used to increase both R@sub Si:As@ and C@sub As@ while providing layers which are atomically flat.