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The oxidation enhanced diffusion (OED) of boron and diffusion as well as recombination of interstitials on silicon-oninsulator (SOI) material have been studied in periodically boron-doped silicon. Bonded wafers (BESOI UNIBOND) as well as oxygen-implanted wafers (SIMOX) have been used to consider different interfacial morphologies. Diffusion experiments were performed in the temperature range of 800 to 1050°C and compared with SUPREM-IV simulation results. Parameters like recombination velocity and diffusivity of interstitials have been extracted. Results show for the first time that OED is effectively reduced in SOI material in the near Si/SiO2-interface region as well as in the surface region.

In this paper we present a study on the dopant and process dependence of the fracture stress of polysilicon films measured in situ using surface micromachined tensile test structures. The micromachined fracture test structures consist of a narrow center beam, loaded by wider beams which are under residual tensile stress. The narrow center beam can be selectively ion implanted to examine the influence of dopants on the fracture strength of the films. A value of 2.84 f 0.09 GPa was extracted for the fracture stress of undoped polysilicon. The values for boron, arsenic and phosphorus doped polysilicon are 2.77 f 0.08 GPa, 2.70 rtr 0.09 GPa and 2.11 f 0.10 GPa, respectively. No statistical significant difference was observed between samples released using concentrated HF or buffered HF. However, a 17% decrease of the fracture stress was observed for a 100% increase in etching time. '