T. Clarysse et al., RECENT INSIGHTS INTO THE PHYSICAL MODELING OF THE SPREADING RESISTANCE POINT-CONTACT, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 14(1), 1996, pp. 358-368
The generation of accurate electrically active dopant profiles from ra
w spreading resistance probe (SRP) data requires a realistic physical
description of the high-pressure point contact used. Comparisons betwe
en SRP and secondary ion mass spectrometry for junction isolated struc
tures have previously indicated a need to introduce, into the one-dime
nsional Poisson calculations, rather high permittivity and band gap na
rrowing values close to the contact. To clarify the situation, a syste
matic survey of the literature has been made regarding the mechanical
and electrical aspects of pressure contacts, including finite element
calculations of the internal stress distributions and the characterist
ics of the high-pressure phases of silicon. Furthermore correlation ha
s been sought with current-voltage curves of the SRP point contact, na
no-SRP low weight measurements, and atomic force microscopy and transm
ission electron microscopy analysis of SRP probe imprints. The emergin
g physical contact model is one dominated under the high-pressure cont
act by a series of 20-50-nm-deep plastically deformed metallic beta-ti
n Ohmic microcontacts embedded in an elastically deformed narrow band
gap and high permittivity region several micrometers deep. On junction
isolated structures the higher permittivity results in an enhanced re
verse carrier spilling effect causing an apparent on-bevel junction sh
ift larger than predicted by zero-field simulations. (C) 1996 American
Vacuum Society.