Kazuhisa Matsumoto

LEC growth of Te-doped GaSb single crystals with uniform carrier concentration distribution

Abstract Large diameter (35–50 mm) Te-doped 〈100〉 GaSb single crystals have been successfully grown from a non-stoichiometric melt by the liquid encapsulated Czochralski (LEC) method. The X-ray transmission topograph shows that the 〈100〉 crystals have extremely low dislocation densities (less than 1 cm −2 ), weak striations and no facets. Hall measurements show that the carrier concentration (7.1×10 18 cm −3 ) distribution is within ±5% deviation over (100) wafers.

Effects of Whole Ingot Annealing on 1.49 eV PL Properties in LEC-Grown Semi-Insulating GaAs

The effects of whole ingot annealing on 1.49 eV photoluminescence (PL) properties at 4.2 K in undoped/low-Cr doped LEC-grown semi-insulating GaAs have been studied. It has been found that whole ingot annealing considerably increases the PL intensities with no significant degradation of semi-insulating properties. It has been also found that whole ingot annealing drastically reduces both the radial variation of PL intensity distribution and the difference of PL intensities between seed end and tail end.

In situ transport rate monitor during ZnSe crystal growth by PVT

Non-stoichiometry of the vapor phase in a growth tube for the crystal growth of ZnSe by physical vapor transport (PVT) was investigated using an in situ transport rate monitor. The unintentional non-stoichiometry by excess Zn was concluded by the dependence of the transport rate on the evaporation temperature.

Crystal growth of ZnSe by PVT using a semi-open ampule

Bulk crystal growth of ZnSe from the vapor phase was conducted. A high reproducibility of the growth rate was obtained using a semi-open ampule into which Ar gas was introduced. The dependence of the growth rate on the growth temperature, measured by in situ growth rate monitoring, indicated that the growth rate was determined by diffusion of component gas in Ar gas with a constant non-stoichiometry.

The effect of gravity on crystal growth of InGaAs by the Bridgman method

Abstract InGaAs crystals were grown by the Bridgman method on earth and in microgravity. The difference of Ga composition profiles in the growth crystals is associated with the difference of heat transfer.

Numerical simulation on dumping of convection by rotating a horizontal cylinder during crystal growth from vapor

Abstract Rotation of a horizontal cylinder is proposed as a new method to suppress the convective transport in the crystal growth from vapor. Numerical calculations are carried out in order to evaluate the effect of this method. The reduction of Sherwood number (Sh) is confirmed and other characteristic features of this method are found as described below. The transient increases of flow velocity accompanied by the transition from the boundary-layer-driven regime (BLDR) to the core-driven regime (CDR), and the occurrence of a counter flow near the center of the crystal surface are found. Though the counter flow causes the nonuniformity of Sh across the interface, the choice of optimum rotational frequency, which enables both reducing Sh and avoiding the nonuniformity of Sh, is presented.