Indium atoms were implanted into silicon oxides to study indium diffusion during annealing and deposition processes. In the thermal oxide, the peak indium concentration decays without marked profile broadening, suggesting that a large fraction of indium is immobile during annealing in nitrogen. Oxygen ambient was found to reduce the decay of the indium peak in thermal oxide. The tail diffusion of indium was observed in thermal oxide after chemical vapor deposition using tetraethoxysilane (TEOS) or SiH 4 as the precursor. The tail diffusion increases as TEOS oxide replaces thermal oxide. However, performing densification annealing before indium implantation reduces the tail diffusion in TEOS oxide. The tail diffusion indicates an increase in the concentration of mobile indium atoms. Experimental results suggest that hydrogen from deposition processes is important in indium tail diffusion.

The diffusion of implanted carbon in preamorphized silicon was investigated with and without phosphorus coimplantation. Coupling effects were observed when carbon and phosphorus diffused simultaneously during junction formation. With an implantation dose of 1 × 10 15 cm −2 , phosphorus diffusion resulted in interstitial supersaturation, enhancing the tail diffusion of carbon. However, the diffusion of carbon was not enhanced when the implantation dose of carbon was increased to 5 × 10 15 cm −2 . This result indicates that high-dose carbon implantation inhibited the interstitial supersaturation that was caused by phosphorus diffusion. Accordingly, the tail diffusion of phosphorus was suppressed and box-shaped diffusion profiles were obtained in the region of high carbon concentration.

In this study, differential Hall measurement (DHM) was developed to measure the carrier profiles in phosphorus doped ultrashallow junctions (USJs). Experiments using uniform phosphorus profiles in silicon on insulator (SOI) wafers demonstrated that the growth rate of the native oxide strongly depends on the phosphorus doping level. Therefore, the thickness of native oxide was monitored by X-ray photoelectron spectroscopy (XPS) to achieve nanometer depth resolution during DHM. The DHM method was applied to investigate the deactivation of phosphorus in laser annealed USJs. The DHM results indicate carrier profile redistribution near the surface due to uphill diffusion caused by phosphorus deactivation.

In this paper, we present MEDICI simulations of the admittance-voltage properties of Ge and Si MOS devices, including analyses of substrate conductance G sub and high-low transition frequency f tran , to explore the differences in the minority-carrier response. The Arrhenius-dependent G sub characteristics revealed that a larger energy loss-by at least four orders of magnitude-occurs in Ge than in Si, reflecting the fast minority-carrier response rate, i.e., a higher value of f tran . We confirmed that the higher intrinsic carrier concentration in Ge, through the generation/recombination of midgap trap levels as well as the diffusion mechanism, resulted in the onset of lowfrequency C-V curves in the kilohertz regime, accompanying the gate-independent inversion conductance. The experimental data obtained from Al 2 O 3 /Ge MOS capacitors were consistent with the values of G sub and f tran obtained from MEDICI predictions and theoretical calculations. In addition, upon increasing the inversion biases, we observed shifts in the G sub /f conductance peaks to low frequencies that mainly arose from the transition of minority carriers with bulk traps in the depletion layer. Meanwhile, we estimated that the bulky defects of ca.(2−4) × 10 15 cm −3 exist in present-day low-doped Ge wafers.

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