Comparative study of two-dimensional junction profiling using a dopant selective etching method and the scanning capacitance spectroscopy method

The importance to industry of a two-dimensional dopant profiling technique becomes more critical as the sizes of the devices shrink. As these techniques develop, their relative reliability comes into question and the only comparisons that exist are with accepted one-dimensional techniques such as secondary ion mass spectroscopy (SIMS) and spreading resistance profiling or with each other. In this article, we make one such comparison between a newly introduced technique of scanning capacitance spectroscopy and a somewhat older technique of selective etching. Based on vastly different principles, these two techniques provide an: opportunity to learn about each through comparison. The results of the comparisons are shown to be consistent both in the qualitative shape similarities of the n-type metal-oxide semiconductor (NMOS) data from both methods and in the quantitative agreement of the lateral junction position under the gate to within 30 nm. The p-type metal-oxide semiconductor (PMOS) data from both techniques differ somewhat in the. channel region due to the fact that under these etching conditions the channel region tends to etch out and at long times can etch out to a point comparable to the true junction. The vertical alignment with SIMS and thus with the etching data is within the 30 nm error margin. The general comparison between the two techniques indicates that the junction is determined at the same point in the lateral direction for the NMOS device, and there is some disagreement on the PMOS junction position under these conditions. (C) 2000 American Vacuum Society. [S0734-211X(00)02001-1].