No abstract

A special solid-phase epitaxy technique utilizing the surfactant B for the growth of crystalline Si-QWs on CaF2∕Si(111) enabled us to grow CaF2∕Si∕CaF2 double-barrier diodes exhibiting resonant tunneling effects from 77K up to room temperature with peak voltages at 0.2eV, which is very close to simple resonant tunneling model predictions. The peak voltages and currents were virtually independent of temperature. No trapping or hysteresis effects were found in the I–V characteristics which exhibited 2–7 orders of magnitude larger peak current densities than previously reported CaF2∕Si∕CaF2 RTDs.

No abstract

Up to now an in-line method for parameter determination of deposited thin polysilicon films is not available. In this paper a method for monitoring the polysilicon deposition process in device manufacturing by variable angle spectroscopic ellipsometry (VASE) is demonstrated. Therefore several polysilicon films are deposited on thermally oxidized [100] silicon wafers. These samples are characterized by VASE in the optical range of 450 - 850 nm. Parameters are determined by simulation using a multilayer model consisting of air, interface layer (surface roughness), polysilicon, SiO2 and silicon substrate. Different optical models representing the properties of polysilicon are tested. The free parameters are the oxide thickness, the composition and the thickness of the interface layer (air, polysilicon) as well as the thickness and the complex refractive index of the polysilicon layer. Results of the spectroscopic analysis are verified by AFM and SEM measurements. It can be shown that parameters of the deposited polysilicon films, which often could only be determined by complex and destructive off-line analysis methods are also accessible by non-destructive in-line VASE measurements.

No abstract