Jon T. Fitch

Comparison of Surface Charge Analysis and MOS C‐V as Techniques for Ionic Impurity Detection in Si / SiO2 Structures

Surface charge analysis (SCA) is a novel technique which utilizes the surface photovoltage (SPV) effect to measure depletion layer widths in silicon. It is demonstrated to be a superior alternative to capacitance-voltage (CV) measurements for the detection of ionic impurities in Si/SiO[sub 2] structures. Not only is SCA demonstrated to have higher resolution but, since it does not require the fabrication of a MOS capacitor, ionic impurity evaluations can be performed much faster than by CV and at a far lower cost. Detailed experiments and statistical analyses comparing the two techniques are presented.

A nonrecessed-base, self-aligned bipolar structure with selectively deposited polysilicon emitter

A self-aligned bipolar structure, which features a nonrecessed base and a selectively deposited polysilicon emitter, is proposed. The in situ surface cleaning process prior to the selective-polysilicon deposition minimizes the residual native oxide in the emitter window. Both high-quality selective-polysilicon film and well-behaved submicrometer bipolar device characteristics have been obtained for bipolar or BiCMOS VLSI applications. The effects of the nonrecessed-base device structure on the bipolar device parameter distribution and bipolar hot-carrier immunity are also discussed. >

Selectivity Mechanisms in Low Temperature (<950°C) Selective Silicon Epitaxy

Low temperature selective silicon epitaxy was studied over a range of process pressures and HCI flows using a SiH 2 Cl 2 /HCl/H 2 based chemistry. Thermodynamic modelling was carried out with the aid of the SOLGAS program to investigate the effect of process pressure, HCI flow rate, and leaks on the distribution of gas phase species. Selectivity results are interpreted in terms of the defect microchemistry on SiO 2 surfaces.