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

Abstract

Development of point defect‐controlled Czochralski silicon (CZ‐Si) 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 hydrogen‐doping technologies are proposed for 300‐mm magnetic‐field‐applied CZ‐Si (MCZ‐Si) crystals free of grown‐in 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 self‐interstitials so that the generation of grown‐in defects, such as voids and dislocation clusters, are suppressed. Nitrogen‐doping or hydrogen‐doping technology combined with v/G control also enables the enlarging of the process window for grown‐in defect‐free MCZ‐Si crystals that can be used as an alternative material to floating zone‐Si 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.

TheASi–SiiDefect Model of Light‐Induced Degradation (LID) in Silicon: A Discussion and Review

“…The explanation of Si i resulting from oxygen clusters suggests a more or less homogenous distribution of oxygen clusters in the as-grown Czochralski silicon crystal. However, in Czochralski silicon crystals, the observed bulk microdefects (BMD) can show depending on the growth process a pronounced pattern, [39,40] which is explained by the Voronkov model. [41,42] This pronounced BMD pattern, see in particular the line scans of Figure 6d of the study by Hourai et al, [40] is linked to vacancy or silicon interstitial-rich regions in the crystal.…”

“…However, in Czochralski silicon crystals, the observed bulk microdefects (BMD) can show depending on the growth process a pronounced pattern, [39,40] which is explained by the Voronkov model. [41,42] This pronounced BMD pattern, see in particular the line scans of Figure 6d of the study by Hourai et al, [40] is linked to vacancy or silicon interstitial-rich regions in the crystal. In an experiment related to these regions, no impact of this pattern on the LID could be found.…”

Gray-box modeling of 300 mm diameter Czochralski single-crystal Si production process

“…All of the above models were built for ingot production processes with a diameter of less than 200 mm. Since 300 mm diameter singlecrystal silicon ingots are currently mass-produced, a model that can represent the dynamic characteristics of the industrial-scale CZ process is required [11].…”

Preferential Growth Mode of Large-Sized Vacancy Clusters in Silicon: A Neural-Network Potential and First-Principles Study

“…Voronkov 2 proposed an analytical model in which the dominant point defect is determined by the value of v/G, where v is the pulling rate and G is the axial thermal gradient at the melt/solid interface. For v/G values larger than the critical value of about 0.2 mm 2 /K min, 3 V is more dominantly formed than I. For the purpose of productivity, conventional CZ-Si crystals are grown under conditions in which v/G values are sufficiently larger than the critical value.…”