No abstract

No abstract

The effect of the first-step heat treatment temperature on the bulk microdefect (BMD) and oxidation-induced stacking fault (OiSF) formation in two kinds of heavily boron-doped silicon wafers, with and without an OiSF ring area, were investigated by comparing it with that in lightly boron-doped wafers. The BMD density was observed to be higher in the heavily doped silicon than in the lightly doped one at the same oxygen concentration. Unlike in the lightly doron-doped silicon, in the heavily boron-doped silicon, OiSFs were formed over the entire wafer surface regardless of the OiSF ring position when the first-step heat treatment was carried out at 900°C.

We reviewed experimental results of the variation of growth parameters bringing forth the axially asymmetric formation of vacancy-interstitial boundary and the increase of the critical growth rate V*, transition from interstitial to vacancy, of Czochralski-grown silicon crystals. Such results show that controlled melt convection for defect-free crystals can make the critical growth rate V* much higher like EMCZ. Some parameters can control interstitial oxygen concentration in the crystal effectively as well. From the cone-shaped shouldering test, asymmetric formation of {111} crystal facets was obtained at very low crucible rotation, which confirms asymmetric distributions of the melt temperature. Based on the results of two dimensional (2D) and three dimensional (3D) simulations, it is shown that the very low crucible rotation rate decreases radial temperature gradient and increases axial temperature gradient in the silicon melt. INTRODUCTIONSemiconductor device makers have asked silicon wafer makers of higher quality substrates appropriate for nano-scale design rule, of lower price. Therefore, some wafer makers have made efforts to reduce the manufacturing cost of defect-free silicon wafers. One of such efforts is increasing the pulling rate to grow the defect-free crystal with sufficient process window. High pulling rate reduces the cycling time of growing crystal by crystal, and thus increases production capacity per crystal grower. Besides, probably it reduces the generation of dislocation during crystal growing. As such, Higher pulling rate is preferred regardless of the crystal quality level. Watanabe et al. reported that high pulling rate of defect-free crystals can be obtained using EMCZ (Electro-Magnetic CZ) method, in addition to easy control of oxygen concentration [1,2,3]. Okui et al. found that the pulling rate of defect-free crystals was increased by changing crucible rotation from 12rpm (rotation per minute) to 1rpm in normal CZ method [4]. Authors have shown that at very low crucible rotation rate much higher pulling rate for defect crystals was possible in normal CZ and MCZ [5,6]. Like EMCZ, melt convection can also be highly controlled by several growth parameters in normal CZ or MCZ.In this study, we reviewed effects of several growth parameters on point defect (vacancy, self-interstitial, oxygen) incorporation into the growing crystal: crucible rotation, crystal rotation, cusp magnetic configuration, and argon gas flow rate. Further, the cone-shaped shouldering test was conducted to confirm the asymmetric distribution of the melt temperature. In the last part, the effect of crucible rotation on the silicon melt temperature ECS Transactions, 3 (4) 31-39 (2006) 10.1149/1.2355743, copyright The Electrochemical Society 31 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.237.-211.38 Downloaded on 2015-07-01 to IP 32field was discussed using two dimensional (2D) and three dimensional (3D) simulation results. EXPERIMEN...