Masakazu Kimura

Gravity effect on dissolution and growth of silicon in the In-Si system

Abstract Epitaxial growth of silicon from an indium solution and dissolution of silicon in the Earths gravitational field are considered. We examined the epitaxial growth and dissolution using a horizontal substrate-solution-substrate “sandwich” system under near isothermal conditions. Remarkable differences between substrates above and below a solution were observed. These phenomena are discussed in terms of the effect of gravity on mass transport in the growth solution. We propose a new growth technique, called the “yo-yo solute feeding method”, using cyclic temperature modulation.

The solute-feeding Czochralski method for homogeneous GaInSb bulk alloy pulling

Abstract A technique of pulling a homogeneous alloy from GaSb-InSb pseudo-binary solution under GaSb solute-feeding conditions has been developed. A two-chamber crucible, in which a small hole controlled solute supply from the source chamber to the growth chamber, realized two conflicting conditions required for stable CZ-mode growth (non-equilibrium) and for keeping a constant composition (near-equilibrium). With the use of a GaSb seed crystal , a GaInSb bulk alloy with uniform InSb content of 3 mol% was pulled at a constant temperature of 691°C. Subsequently, using this grown alloy as the second seed, an alloy of 15 mm diameter and 20 mm lenght with InSb content of 5 mol% could be pulled at 672°C.

Gravity effect on solute transport in dissolution and growth of silicon

Dissolution of silicon in an indium solution in the Earths gravitational field is considered. We examined the dissolution using a substrate-solution-substrate “sandwich” system under near isothermal conditions. A remarkable difference was observed between substrates above and below the solution. This phenomenon is discussed in terms of solutal convection in the solution. A numerical description of this convection and its effect on the dissolution process is given. Comparison with experimental data shows that the observed phenomenon can be explained on the basis of the solutal convection model.

Bipolar-mode static induction transistor: experiment and two-dimensional analysis

A bipolar-mode static induction transistor (BSIT) with a simple planar structure as an experimental device has been fabricated. Two-dimensional numerical simulation has been used to investigate the operational principle for the BSIT with the pentode-like shape revealed by the output characteristics. Using the simulation, the variation of the potential barrier as a function of the bias voltages has been explained. The results show that the potential barrier is varied uniquely according to the physical condition of the conduction channel determined by the external bias voltages. This variation can be explained easily with the DC circuit models originating from the physical conditions of the conduction channel. The analysis shows that the current in the BSIT is controlled in a complex manner by the voltages. >

Control of GaInSb alloy composition grown from ternary solution

Abstract The solute-feeding Czochralski method developed to grow a homogeneous bulk alloy from a pseudo-binary solution has been expanded to a ternary solution system. To keep the alloy composition constant, two parameters of growth temperature and source composition were fixed. By establishing a special growth condition, the alloy composition was prevented from thermal disturbance. The growth of a homogeneous Ga 0.4 In 0.6 Sb alloy is demonstrated.

Multi-step pulling of GaInSb bulk crystal from ternary solution

Abstract The solute feeding Czochralski method was applied to the growth of GaInSb alloy from Ga–In–Sb ternary solution. At first, an alloy with 0.04xa0GaSb mole fraction was grown on an InSb(1xa01xa01)B seed. Using the grown alloy as a seed, an alloy with 0.08xa0GaSb mole fraction was pulled. By adopting a small step in composition less than 0.05, single-crystal growth was maintained in every step. After four steps, the alloy composition of 0.17xa0GaSb mole fraction was achieved. Wafers of about 10xa0mm diameter with etch pit density of (5–6)×10 4 xa0cm −2 can be produced.

Preparation of lithium niobate films by metalorganic chemical vapor deposition with a lithium alkoxide source

Li(OBut) was examined as a Li source in low pressure metalorganic chemical vapor deposition (LP-MOCVD). Vapor species of Li component and Nb component (from a Nb (OEt)5 source) carried with argon gas were blown on a SiO2Si substrate heated at 450–630°C. The deposited films were confirmed to be crystalline LiNbO3 by X-ray diffraction.

Convection phenomenon during the dissolution of silicon in an indium solution

Abstract The effect of solutal convection on mass transport during the dissolution of silicon is discussed. We examined the dissolution of silicon using a substrate-solution-substrate “sandwich” system under near isothermal conditions. A remarkable difference was observed between the substrates above and below the solution. This phenomenon is discussed in terms of solutal convection in the solution. To describe the experimental results, numerical simulation of dissolution process is given. Calculated results show that the observed phenomenon can be explained on the basis of the solutal convection model with consideration of surface reaction.

LPE GROWTH OF SILICON BY YO-YO SOLUTE FEEDING METHOD

Abstract Stripe lines were observed on stained cross-sections of epitaxial layers of silicon grown by yo-yo solute feeding method using indium solvent. These stripe lines were found to be flat and parallel to the interface between the epitaxial layer and the substrate. The origin of these lines is discussed and it is made clear that the growth occurs in each cycle of yo-yo temperature repetitions.

Growth of GeSi thick alloy layers by the yo-yo solute feeding method

Abstract Ternary phase diagrams of the Sn-Ge-Si system at 900 and 950°C have been made clear theoretically and experimentally. The growth technique of thick layers of Ge x Si 1− x alloy on Si(111) substrates using Sn solvent has been developed. Thick layers of about 800 μm with 0.24 Ge mole fraction were successfully obtained by the yo-yo solute feeding method with 88 yo-yo repetition times between 980 and 960°C.