L. G. Lavrent'eva

Doping and impurity-vacancy complex formation during vapour-phase epitaxy of gallium arsenide

Abstract The kinetics of the incorporation of impurities in the form of donors, acceptors and impurity-vacancy complexes (IVC) was studied experimentally for VPE GaAs doped with group IV and group VI impurities (Ge, Sn, S, Te). It was found that the concentration of donors increases linearly, whereas the IVC concentration appears to increase quadrically with the impurity pressure. A model of impurity incorporation is discussed, according to which the simple substitution occurs due to the capture of absorbed atoms, and the IVC formation is caused by the capture of adsorbed diatomic impurity molecules with their subsequent dissociation.

Low-Temperature Molecular-Beam Epitaxy of GaAs: Effect of Excess Arsenic on the Structure and Properties of the GaAs Layers

The present paper reviews works devoted to control over the properties of epitaxial GaAs by incorporation of excess (non-stoichiometric) arsenic into the GaAs films grown by molecular-beam epitaxy (MBE) at low-temperature (LT). The effect of excess arsenic on the material structure and properties is analyzed for both as-grown and annealed LT-GaAs layers. The effect of doping on the incorporation of excess arsenic is also examined. The data on the effect of excess arsenic on the properties of the Ga0.47In0.53As solid solution are presented. The specific features of the mechanism of the excess arsenic incorporation into the solid phase during the low-temperature epitaxial growth are discussed.

Formation of a transition layer during heteroepitaxy of III–V compound semiconductors in gas-phase epitaxy systems

It is known that during gas-phase epitaxy of InP and GaAs the region of the film close to the heteroboundary is formed with altered phase, structural, and electrophysical properties. The main cause for this is formation of a transition layer due to a change in the growth mechanism (transition from nucleational to layer-step growth) and the structure of the growing surface (height and density of growth steps).

Formation of centers with deep levels in gaseous phase epitaxy of gallium arsenide

The authors review the experimental research of the last decade into the laws of formation of the defects responsible for the deep levels in epitaxial layers of gallium arsenide grown from the vapor phase. The topics of their review include the influence of the ratio of the pressure of As and Ga in the vapor phase on defect concentration, the role played by the defects in carrier lifetime, density and mobility as well as in the ultimate electrical and photo conductivity of the material, the behavior of various feedstocks and impurities and their contributions to defect structure, and the dependence of defect concentration on growth conditions.

Anisotropy of the growth rate and doping level of self-epitaxial germanium in the crystallographic range (111)-(100)

The orientation dependences of the morphology, growth rate, and doping levels of epitaxial germanium films were studied in the range (111)-(100). The smoothest surface corresponds to films some 10–40 ° from the (111) plane toward the (100) plane. The growth rate decreases at angles up to 10 ° from the (111) and (100) planes and then begins to increase, reaching a maximum at (311). The doping level decreases as the growth rate increases. The results are discussed on the basis of the crystal-growth model of Burton-Cabrera-Frank and Chernov.

Influence of the Substrate Orientation on the Silicon Capture into A- and B- Sublattices of Gallium Arsenide in Molecular Beam Epitaxy

The influence of crystallographic orientation of the growth surface near (100) and (111)A GaAs singular faces on the silicon capture into A- and B-sublattices of gallium arsenide in molecular beam epitaxy is investigated by the electrophysical and photoluminescence methods. It is demonstrated that the silicon dopand is incorporated into GaAs layers not only as simple SiGa donors but also as elemental SiGa acceptors and more complex defects, namely, SiAs–VAs complexes. The concentration of defects of different types in layers depends on the orientation of the growth surface, and the amphoteric properties of silicon on the (111)A face are manifested stronger than those on the (100) face.

Interaction of Growth Steps on the Surface of InAs Epitaxial Layers in Vapor-Phase Epitaxy

The influence of concentrations of vapor-phase growth components on the structure of singular, vicinal, and nonsingular growth surfaces of InAs epitaxial layers grown in the In–AsCl3–H2 system is investigated by the methods of electron microscopy. It is established that the average distance λ between steps in the echelon increases as the input pressure PAsCl3 increases in the range 70–700 Pa and then approaches a constant value λ when PAsCl3 > 700 Pa. The observed dependences λ(PAsCl3) are explained within the framework of the model of diffusion interaction of steps.

Effect of the Arsenic Concentration on the Characteristics of the Growth Step Echelon in GaAs Epitaxy

The effect of the arsenic concentration in the vapor phase on the growth step distribution over the surface of GaAs epitaxial layers grown in a chlorine-hydride vapor-transport system on substrates with 4° (111)A and (113)A orientations is studied. It is demonstrated that the average distance between steps in the echelon depends on the arsenic concentration and increases with it up to a certain constant value. It is assumed that this is connected with the change in the kink density at the steps.

Study of the surface processes in vapor-phase epitaxial GaAs: Asymmetric trapping of atoms at the step

Experimental proofs of asymmetric trapping of atoms at the growth step in vapor-phase epitaxy of gallium arsenide in the GaAs–AsCl3–H2 system are given. The data obtained confirm the important role of the surface diffusion mass transfer in the growth of epitaxial GaAs layers on vicinals in the neighborhood of (111)A. The effective diffusion length is estimated.

Structure and properties of epitaxial GaAs and InGaAs films grown by low-temperature molecular-beam epitaxy

We study epitaxial GaAs and InGaAs films produced by molecular-beam epitaxy in the temperature range 150–480°C and with various arsenic partial pressures. We determine the structural and electrophysical characteristics of the film (the excess arsenic, the crystal lattice parameter, and the carrier concentration and mobility) as a function of the growth conditions. The influence of annealing on the cluster-structure formation in low-temperature MBE films, and on their properties, is also studied. In low-temperature GaAs we find a characteristic microwave absorption signal indicating the presence of a superconducting phase. We discuss the possible nature of this phase with regard to clusters of gallium or an In-Ga alloy.