The effects of hydrostatic pressure on the solid-phase epitaxial growth (SPEG) rate v of intrinsic Ge(100) and undoped and doped Si(100) into their respective self-implanted amorphous phases are reported. Samples were annealed in a high-temperature, high-pressure diamond anvil cell. Cryogenically loaded fluid Ar, used as the pressure transmission medium, ensured a clean and hydrostatic environment. v was determined by in situ time-resolved visible (for Si) or infrared (for Ge) interferometry. v increased exponentially with pressure, characterized by a negative activation volume of −0.46Ω in Ge, where Ω is the atomic volume, and −0.28Ω in Si. The activation volume in Si is independent of both dopant concentration and dopant type. Structural relaxation of the amorphous phases has no significant effect on v. These and other results are inconsistent with all bulk point-defect mechanisms, but consistent with all interface point-defect mechanisms, proposed to date. A kinetic analysis of the Spaepen–Turnbull interfacial dangling bond mechanism is presented, assuming thermal generation of dangling bonds at ledges along the interface, independent migration of the dangling bonds along the ledges to reconstruct the network from the amorphous to the crystalline structure, and unimolecular annihilation kinetics at dangling bond ‘‘traps.’’ The model yields v = 2 sin(θ)vsnr exp[(ΔSf + ΔSm)/k] exp− [(ΔHf + ΔHm)/kT], where ΔSf and ΔHf are the standard entropy and enthalpy of formation of a pair of dangling bonds, ΔSm and ΔHm are the entropy and enthalpy of motion of a dangling bond at the interface, vs is the speed of sound, θ is the misorientation from {111}, and nr is the net number of hops made by a dangling bond before it is annihilated. It accounts semiquantitatively for the measured prefactor, orientation dependence, activation energy, and activation volume of v, and the pressure of a ‘‘free-energy catastrophe’’ beyond which the exponential pressure enhancement of SPEG cannot continue uninterrupted due to a vanishing barrier to dangling bond migration. The enhancement of v by doping can be accounted for by an increased number of charged dangling bonds, with no change in the number of neutrals, at the interface. Quantitative models for the doping dependence of v are critically reviewed. At low concentrations the data can be accounted for by either the fractional ionization or the generalized Fermi-level-shifting models; methods to further test these models are enumerated. Ion irradiation may affect v by altering the populatio

The gettering of ion implanted Au to defects in Si has been studied using Rutherford backscattering and channeling and transmission electron microscopy. Damage from a Si implant anneals into dislocations which can efficiently trap diffusing Au. The damage introduced by a H implant evolves during annealing into cavities which getter close to 100% of the Au, leaving very little Au in solution. This process is driven by the diffusion of a supersaturated solid solution of Au to a favorable sink. The internal surfaces of cavities are the most favorable sink, followed by dislocations and then the Si surface.

We have measured the effect of pressure on the solid phase epitaxial growth rate of Ge(100) into self-implanted amorphous Ge by using in situ time-resolved infrared interferometry in a high-temperature, high-pressure diamond anvil cell. In the temperature range 300–365 °C, a rate enhancement of more than a factor of 100 over that at ambient pressure has been observed due to hydrostatic pressures of up to 5.2 GPa (52 kbar). The pressure enhancement is characterized by a negative activation volume of −6.2±0.6 cm3/mol (−45% of the atomic volume), which is of the same sign but greater in magnitude than we found in Si. We conclude that the defects controlling the solid phase epitaxy of Ge cannot be vacancies in the crystal, that mechanisms based on other point defects migrating to the interface from either phase are unlikely, and that mechanisms based on point defects residing in the interface are plausible.

We have measured the crystal growth rate u of B2O3-I in the amorphous phase, as it varied over five orders of magnitude with changes in temperature and pressure. We eliminated the crystal nucleation barrier by seeding the surface of boron oxide glass with crystals. u became measurable only when the pressure exceeded a threshold level near 10 kbar. Using the published thermodynamic information on the B2O3 system and a crude free-energy model for the crystal and glass phases, we account qualitatively for our results with the theory of crystal growth limited by the rate of two-dimensional nucleation of monolayers. The constants for the prefactor, activation energy, activation volume, and ledge tension are determined by fitting. By adjusting the thermodynamic parameters to a set of values that are well within the ranges delineated by their experimental uncertainties, we account quantitatively for the measured growth rates from 300 to 500 °C and from 0 to 30 kbar with the following relation: u(T,P)=(785 m/s)[‖ΔGm‖/(RT)]1/6 ×exp[π×3 Å(420 erg/cm2)2(28 cm3/mole)/(3 kTΔGm)]exp[−10 366 cal/mole/(RT)] ×exp[−P×16 cm3/mole/(RT)]×{1−exp[ΔGm/(RT)]}2/3, with the driving free energy given by ΔGm(T,P)=(13 cm3/mole) [PM(T)−P] and the melting curve given by PM(T)=(T−450 °C)/(42.6 K/kbar). The ‘‘B2O3 crystallization anomaly’’, that crystals have never been observed to grow at atmospheric pressure, is explained, since according to our model, the frequency of two-dimensional nucleation is negligible at all temperatures at pressures less than 10 kbar.

The hydrostatic pressure dependence of the solid phase epitaxial growth rate of 〈100〉 Si into ion implanted amorphous Si at 500 °C has been monitored by Rutherford backscattering and channeling techniques. The growth rate increases with pressure so that at 20 kbar it is 14 times the ambient value. The increase is described by an activation volume for the process of −8.7 cm3/mole.