Pinchon, P. M.
R.T.C La Radiotechnique Compelec, 14 Caen,
Pages: 11 Published: Jan 1974
The correction factors in spreading resistance measurements are generally determined by using a plan-parallel model of a single or multi-layer structure. This paper will discuss the applicability of these factors to the profiling measurements on a bevel, and call attention to possible systematic errors which can appear in the case of an insulated layer or a low/high type of structure. After a short discussion on the spacial resolution of the spreading resistance probe, the case of a homogeneous isolated layer is examined in more detail. A simplified expression for the value of spreading resistance was calibrated against published data using fitting coefficients. It is then easy to show that the use of a correction derived for parallel structures is not correct for the case of a thin, isolated layer, when the measurement is made on a bevel. Indications are also given on the parameters which could minimise the problem The experimental part of this paper shows a series of profiles made with P-type epitaxial layers. After the application of the usual corrections, the various electrical boundaries or geometrical conditions are seen to affect the results in accordance with the discussion. An edge effect which is significant even at great distance from the edge, is also described. In the absence of a three dimensional theory for correction, the use of small spacing is recommended in conjunction with a small radius of contact and a shallow bevelling angle.
Accuracy, bevelled structures, correction application, correction factors, edge effect, profiles, resistivity profiling, small spacing, spreading resistance
Paper ID: STP47394S