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Recent studies including our own report (I) have revealed that heavily phosphorus (P) doped Czochralski-silicon (HP-Cz-Si) exhibits peculiar defect behaviors during crystal growth. HP-Cz-Si crystals with a low resistivity of around 0.6 mΩ cm (P concentration of 1.3 × 1020 P cm−3) have interstitial-type stacking faults (SFs) and dislocations, which degrade device characteristics. The purpose of this paper is to clarify what causes the defect behavior in HP-Cz-Si through theoretical calculations. The thermal equilibrium concentrations of substitutional P (Ps), interstitial P (Pi), and (Ps)n-vacancy (V) clusters (n = 1−4) were determined by using density functional theory (DFT) calculations. The concentrations of Pi ([Pi]) and (Ps)nV ([(Ps)nV]) balanced with the given Ps concentration ([Ps]) were obtained as a function of the total P concentration ([P]) and the temperature. On the basis of the calculated results those can quantitatively explain our experimental results in the report (I), we propose a defect model that accurately represents HP-Cz-Si crystal growth. The main feature of the model is that the incorporated Pi atoms at the solid/liquid interface around [Pi] = 1017 Pi cm−3 cause the formation of SFs and dislocations during the HP-Cz-Si crystal growth with around [P] = 1020 P cm−3. Furthermore, DFT calculations were performed for Pi segregation on the SF and for the photoelectron spectra of P 1s measured by hard x-ray photoelectron spectroscopy to explain the other experimental results in the report (I). [ABSTRACT FROM AUTHOR]

This report (I) aims to investigate defect behavior during the growth of heavily phosphorus (P)-doped Czochralski silicon (HP-Cz-Si) crystals. The defects and P chemical states in as-grown crystals with a resistivity of 0.6 mΩ cm and the wafers annealed at around 600 °C were evaluated by transmission electron microscopy and hard x-ray electron spectroscopy (HAXPES). Micro-dislocation loops (MDLs) were observed in the bottom portion of the crystal, and larger stacking faults (SFs), including complex dislocation clusters, were observed in the middle portion. HAXPES revealed two different P states, P1 and P2. P1 was attributed to a substitutional P (Ps). The P2 present in as-grown crystals was found to be electrically active, while the newly formed P2 after annealing was electrically inactive, indicating that they are in different states. HAXPES evaluation of HP-Cz-Si after electron irradiation showed similar behavior to P2 after annealing, suggesting that P-vacancy (V) clusters are formed when the crystals are held at temperatures below 600 °C during crystal growth. Combining the experimental results with our theoretical analysis in the report (II) based on density functional theory calculations, we identified the following defect formation mechanisms. Interstitial P (Pi) atoms introduced at the melting point become supersaturated during cooling to 600 °C, and MDLs are generated by the aggregation of Si self-interstitials (Is) released through a position exchange from Pi to Ps. In crystal portions with a long residence time below 600 °C, supersaturated Ps transforms into P–V clusters, and Is generated simultaneously are absorbed by the MDLs, which grow into SFs containing dislocation clusters. [ABSTRACT FROM AUTHOR]