The behavior of oxygen precipitation in heavily doped silicon was investigated. The experimental results showed that the behavior of oxygen precipitation in heavily doped silicon is not only related to initial oxygen concentration, but also is affected by dopant species. The growth of oxygen precipitation was not affected by dopant type. Dopant species only influenced the nucleation of oxygen precipitation, and the time of precipitate nucleus formation is shorter in P+ samples than in N+ samples. The morphology of oxygen precipitation is independent of dopant type and only depends on the heat-treatment cycles. Considering the hanging bond on the interface of Si-SiO at precipitates embryo and amending the free energy item, an expression of nucleation critical radius associated with dopant species was derived, and the dependent relationship of oxygen precipitation behavior in heavily doped silicon and dopant species was explained by this model. Moreover, an effective intrinsic gettering cycle with suitable width of denuded zone in heavily Sb-doped silicon samples was obtained in order to reduce or eliminate the metallic impurities and unwanted defects in the surface of substrate and device active regions.

Flow pattern defects (FPDs) is one kind of grown-in defects in large diameter Czochralski silicon (Cz-Si) crystals. The evolution of FPDs in lightly doped Cz-Si crystals during secco etchant (50% HF: 0.15 mol L-1 K2Cr2O7=2:1) etching process, was studied in detail firstly. The results also showed that the outline of FPDs became larger and the voidon the tip of FPDs changed into a shallow hole with the increasing of etching time. A parabola model was firstly put forward to explain the evolution of FPDs in Cz-Si wafers during the procedure. Furthermore, the microstructure of FPDs was observed by optical microscopy andatomic force microscopy, the results showed that the outline of FPDs was parabola with several steps and two heaves were firstly foundon the left and right sides of the voidon the tip of FPDs. All the results provide forceful evidence to that FPDs is one kind of void-type as-grown defects. These are very useful to investigate FPDs in Cz-Si wafers further and explain the annihilation of FPDs during high temperature annealing processes.

In this paper, the theory analysis and experiments on the semiconductor silicon crystal growth under the equivalent micro-gravity, which induced by a permanent magnetic field, were investigated. The experimental results show that the crystal growth in the equivalent micro-gravity is similar to that in the space. The homogeneity of doping and the oxygen concentration in CZSi by using the permanent magnetic field, can be improved, because of restriction of the convection, compared with the crystal growth in the conventional CZ method. Diffusion kinetics are dominated during movement of mass in melt under the equivalent micro-gravity, different from that in the conventional CZ method.

The characteristics and annealing behavior of vacancy clusters in neutron transmutation doped silicon (NTDSi) were investigated by means of Fourier transform infrared spectroscopy (FTIR) and photoinduced transient spectroscopy. FTIR results showed that three IR absorption peaks at 707, 742, and 776 cm-1 occurred during annealing NTDSi samples at temperatures ranging from 350 to 600℃. By comparing the present results with those reported earlier, the defect center (we named it the P0 center) which gives rise to these IR absorption bands, was assumed to be a multivacancy cluster consisting of at least six vacancies. Photoinduced transient spectroscopy results showed that a P0 center introduced two acceptor levels at EC-0.427 eV and EC-0.524 eV inside the energy gap.

In this investigation, Czochralski grown silicon (CZ-Si) was irradiated by a fast neutron which can introduce irradiated defects into silicon and change the quality and density of point defects in silicon, by the interaction between irradiated defects and oxygen, the controlled precipitation of oxygen, and an excellent intrinsic gettering structure in CZ-Si during heat treatment cycles can be obtained easily.