Peculiarities of the Impurity Redistribution under Ultra-Shallow Junction Formation in Silicon

Ultra-shallow junctions (USJs) were formed by low-energy As ion implantation with the subsequent furnace annealing. It was found that the significant amount of oxygen is redistributed from the silicon bulk to the arsenic-implanted region. We present the effect of oxygen gettering at the creation of arsenic-doped USJs using the marker layer created by ion implantation of 18O isotope.

4H-SiC Oxide Characterization with SIMS Using a 13C Tracer

The SiO2/SiC interface is characterized for carbon accumulation using the carbon isotope 13C as a marker layer combined with secondary ion mass spectroscopy (SIMS). SiC was epitaxially grown using an isotopically enriched propane source and subsequently oxidized to a thickness required to consume the entire 13C layer. Mass specific depth profiles through the oxide film yield residual carbon concentrations at or below 3x1011 cm-2. The depth resolution of SIMS and natural abundance of 13C in the bulk SiC film limit sensitivity but allow us to set a limit of 2.5x1014 cm-2 carbon build up at or near the interface.

Modeling Ultra Shallow Junctions Formed by Phosphorus-Carbon and Boron-Carbon Co-implantation

A new carbon-interstitial clustering model has been developed. The model has been implemented into the process simulator Sentaurus Process. Model parameters have been calibrated using fundamental marker layer experiments. B diffusion retardation in the C doped layer as well as Sb diffusion enhancement in the region close to a layer with high C concentration are successfully simulated. The calibrated model has been applied to simulations of ultra-shallow junction formation by high dose P-C and B-C co-implantation. It is assumed that, in regions which are amorphized by ion implantation and recrystallized by solid phase epitaxy, C is in the substitutional state right after the recrystallization. In contrast, in non-amorphized regions, C is assumed to be in clusters at the beginning of thermal annealing. A good agreement between simulation and experimental results has been achieved. The dependence of dopant diffusion on implanted C dose and spike annealing temperature has been reproduced.

The Effect of Fluorine Implantation on Boron Diffusion in Metastable Si0.86 Ge0.14

ABSTRACTThis paper investigates the effect of varying F+ implantation energy on boron thermal diffusion and boron transient enhanced diffusion (TED) in metastable Si0.86Ge0.14 by characterising the diffusion of a boron marker layer in samples with and without P+ and F+ implants. The effect of two F+ implantation energies (185keV and 42keV) was studied at two anneal temperatures 950°C and 1025°C. In samples implanted with P+ & 185keV F+, the fluorine suppresses boron transient enhanced diffusion completely at 950°C and suppresses thermal diffusion by 25% at 1025°C. In samples implanted with P+ & 42keV F+, the fluorine does not reduce boron transient enhanced diffusion at 950°C. This result is explained by the location of the boron marker layer in the vacancy-rich region of the fluorine damage profile for the 185keV implant but in the interstitial-rich region for the 42keV implant. Isolated dislocation loops are seen in the SiGe layer for the 185keV implant. We postulate that these loops are due to the partial relaxation of the metastable Si0.86Ge0.14 layer.

Influence of Arsenic Clustering and Precipitation on the Interstitial and Vacancy Concentration in Silicon

ABSTRACTThe point defect injection from arsenic precipitation was studied using boron marker layers and antimony doped superlattices. Comparisons of arsenic and germanium amorphizing implants showed similar boron marker layer diffusion enhancements after spike annealing. The results indicate that the end of range damage caused by the implants was the source of the diffusion enhancement. Additional annealing cycles showed that there was retardation in the diffusion enhancement of the boron marker layers for precipitation range arsenic implants. Antimony marker layers showed no diffusion enhancement due to vacancy injection. The results of the experiments indicate that arsenic-interstitial complexes are the cause of the decrease flux of interstitials to the bulk.