We have developed a new rare-earth calcium oxyborate crystal Gd_xY_<1-x>Ca_4O(BO_3)_3 (Gd_xY_<1-x>COB) in order to control the birefringence in nonlinear optical crystals. Gd_xY_<1-x>COB (0<x<1) crystals with uniform composition have been grown by the Czochralski method. The non-critical phase matching (NCPM) wavelength for second harmonic generation (SHG) has successfully been tuned in the range from 830 to 970 nm by changing the compositional parameter x. Furthermore, we have succeeded to generate NCPM third harmonic of Nd: YAG laser radiation (1064 nm)
The melting and freezing processes of silicon were investigated by in-situ high resolution transmission electron microscopy (HRTEM) and image processing. Atomic structures of (111) interface planes of the solid and liquid phases have been examined. It is revealed that the interface goes back and forth by the lateral motion of atomic steps on (111) planes as the temperature is changed. A transition region of about 1nm thickness is found to exist between the solid and liquid phases.
Due to the size reduction of advanced ULSIs to subquarter micron level, the influence of grown-in defects appearing in Czochralski-grown silicon (CZ-Si) crystals on the device performance and yield has been widely recognized. Therefore, grown-in defect free crystals are strongly required. In this paper, we will discuss the generation behavior of grown-in defects, based on results obtained up to the present. In addition, we will argue the possibility of grown-in defect free crystals and show that V/G, i.e., the ratio of a growth rate (V) to an axial temperature gradient (G) in the crystals at high temperatures near the melting point, is a key parameter to realize grown-in defect free crystals in the near future which are equivalent to epitaxial wafers in crystal quality.
Monte Carlo simulation of the unidirectional melt growth is performed to study the solidification process and the taking-in process of impurities at the solid-melt interface. It simulates the Czochralski Silicon growth by using the diamond lattice. The equilibrium and effective distribution coefficients can be evaluated by the simulation. The nucleation of impurity occurs in the melt and the growth is not steady when the interaction of impurity is strong. The structure of growing solid-melt interface is also investigated. The interface of  growth is flat in the atomic scale. On the other hand, that of  growth is very rough. Then, the growth modes are different by the different crystal orientation of interface. The larger concentration of impurity causes the diffuser interface. The interaction between solid atom and impurity flattens such interface because of more impurities incorporated by the solid.
The recent development of InP crystal growth technologies is reviewed. The improved liquid encapsulated Czochralski (LEC) methods based on thermal baffles are successfully applied to grow 50 mm diameter LEC InP with low dislocation densities. For growing InP crystals with the diameter larger than 75 mm for applications to electronic devices, the pressure controlled LEC methods were firstly developed and are now applied in production scale. The vertical gradient freezing (VGF) method which has the potentiality in growing lower dislocation density crystals had a difficulty in growing <100> single crystals because of twinning occurrence. This difficulty was however solved by the recent development in the VGF method. 100 mm diameter VGF <100> single crystals with the dislocation density level of 2000 cm^<-2> can be successfully grown.