A Spreading Resistance Technique for Resistivity Measurements on Silicon

Abstract

A technique for determining local silicon resistivity from the measured spreading resistance associated with a metal to semiconductor, small‐area pressure contact is described. The major problems encountered in earlier attempts to derive quantitative resistivity data from small area pressure contacts on silicon have been circumvented by making the measurements at bias levels of a few millivolts and by using a particular osmium‐tipped probe arrangement to provide contact reproducibility. The method provides a three‐dimensional spatial resolution in resistivity measurements on silicon on the order of 1μ, and, using a calibration curve determined for a particular silicon surface finish, yields an experimental reproducibility ≤15% for sample resistivities in the range 10−3 normalohm‐normalcm≤ρ≤500 normalohm‐normalcm . Several examples of the application of the technique to problems of current interest in silicon technology are given.

Growth of epitaxial silicon layers by ion beam sputtering

“…The resistivity of sputtered epitaxial layers was checked using the 2-point probe method (Mazur and Dickey 1966) which was particularly suitable for thin layers about 1p thick. The error in each individual measurement was about 15%.…”

Methods of measurement for semiconductor materials, process control, and devices :

“…A summary of early work which led to the establishment of the Joint Program has been prepared [5]. This summary contains a bibliography which includes all NBS publications which were issued in this field prior to the formation of the Joint Program.…”

“…At present it is possible to measure impurity concentration in the range between 5 x 10 *°c m -3 and 2 x io 20 cm -3…”

“…In case 5 both the probe and the specimen were displaced from the center of rotation by 1.5 mm in such a way that the probe position varied from the center of the specimen to a point 3 mm from the center.…”

“…Both resistivity and contact resistance are to be measured on wafers with lapped, mechanically polished, and chemically polished surfaces. Some measurements made on lapped surfaces ahve shown an erratic behavior, hence they are being repeated before proceeding to polished surfaces Probes along radius measuring spreading resistance have been reported [5,6]. Although each of these is reported to yield highly reproducible results, the factors which must be controlled to enable adequate precision on inter comparison of the various methods are not fully recognized.…”