Review and Comments for the Development of Point Defect-Controlled CZ-Si Crystals and Their Application to Future Power Devices

摘要

Development of point defectcontrolled Czochralski silicon (CZSi) crystal growth technology by v/G control, i.e., the ratio of growth rate (v) to the axial temperature gradient (G) in the crystal near its melting point, is reviewed and nitrogen and hydrogendoping technologies are proposed for 300mm magneticfieldapplied CZSi (MCZSi) crystals free of grownin defects with very low oxygen for application to future silicon power devices such as insulated gate bipolar transistors (IGBTs). Using a hot zone with a uniform G distribution in a crystal radial direction, v/G is maintained by controlling v of around the critical value at which the amount of vacancies is balanced with that of selfinterstitials so that the generation of grownin defects, such as voids and dislocation clusters, are suppressed. Nitrogendoping or hydrogendoping technology combined with v/G control also enables the enlarging of the process window for grownin defectfree MCZSi crystals that can be used as an alternative material to floating zoneSi crystals. The advantages and disadvantages of both technologies are discussed from the view point of crystal quality required to guarantee higher performance of future IGBTs.