Abstract
Electrical resistivity distribution maps have been constructed for single crystal silicon wafers cut out of different parts of Czochralski grown ingots. The general inhomogeneity of the wafers has proven to be relatively high, the resistivity scatter reaching 1–3 %. Two electrical resistivity distribution inhomogeneity types have been revealed: azimuthal and radial. Experiments have been carried out for crystal growth from transparent simulating fluids with hydrodynamic and thermophysical parameters close to those for Czochralski growth of silicon single crystals. We show that a possible cause of azimuthal electrical resistivity distribution inhomogeneity is the swirl-like structure of the melt under the crystallization front (CF), while a possible cause of radial electrical resistivity distribution inhomogeneity is the CF curvature. In a specific range of the Grashof, Marangoni and Reynolds numbers which depend on the ratio of melt height and growing crystal radius, a system of well-developed radially oriented swirls may emerge under the rotating CF. In the absence of such swirls the melt is displaced from under the crystallization front in a homogeneous manner to form thermal and concentration boundary layers which are homogeneous in azimuthal direction but have clear radial inhomogeneity. Once swirls emerge the melt is displaced from the center to the periphery, and simultaneous fluid motion in azimuthal direction occurs. The overall melt motion becomes helical as a result. The number of swirls (two to ten) agrees with the number of azimuthally directed electrical resistivity distribution inhomogeneities observed in the experiments. Comparison of numerical simulation results in a wide range of Prandtl numbers with the experimental data suggests that the phenomena observed in transparent fluids are universal and can be used for theoretical interpretation of imperfections in silicon single crystals.
Reference25 articles.
1. Gorelik S.S., Dashevsky M.Ya. Materialovedenie poluprovodnikov i dielektrikov [Materials science of semiconductors and dielectrics]. Moscow: Izd-vo MISiS, 2003, 388 p. (In Russ.)
2. Handbook of Crystal Growth. Vol. 2 Bulk Crystal Growth. Edited by Hurle D.T.J. Amsterdam; London; New York; Tokyo: North-Holland Elsevier Science Publishers, 1994, 1352 p.
3. Kasap S.O. Principles of electronic materials and devices. Boston: McGraw-Hill, 2002, 745 p.
4. Grouping by bulk resistivity of production-line mono-crystalline silicon wafers and its influence on the manufacturing of solar cells modules
5. On the shape of n-type Czochralski silicon top ingots
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献