Accurate Sheet Resistance Measurement on Ultra-Shallow Profiles

Abstract

The accurate and reliable characterization of the sheet resistance of ultra-shallow (USJ) profiles is a key issue in the development of future CMOS technologies. Typically, conventional means, such as in-line four point probe measurements, have a limited accuracy due to the substrate contribution resulting from too much probe penetration, especially in the presence of highly doped underlying layers (such as well/halo-profiles). In this work, a series of advanced Boron doped layers (132 nm down to 2 nm) have been grown with Chemical Vapor Deposition (CVD) on medium and lowly doped substrates and have been characterized with a large variety of state-of-the art non-penetrating/non-contact sheet resistance tools.

High precision micro-scale Hall effect characterization method using in-line micro four-point probes

“…In practical experiments it is difficult to position the electrodes closer than Yo = 4 Jlm from the barrier because this is done optically. Thus, we choose this position for the measurement of 5 (2). For each~y, 500 independent simulations were performed for a 20 Jlm pitch four-point probe.…”

“…Prior experimental work has revealed the need for characterization techniques like the micro four-point probe (M4PP) to accurately characterize sheet resistance of ultra shallow junctions (USJ) [2] with high spatial resolution [3]. Recently, we demonstrated the ability to perform reproducible micro Hall effect measurements to characterize sheet carrier 978-1-4244-1951-7/08/$25.00 ©2008 IEEE density and mobility of shallow implants in both Si and Ge using M4PP [4].…”

Precision of single-engage micro Hall effect measurements

“…Resistance measurements using micro four-point probes (M4PP) [4] is a well-established technique used to monitor the sheet resistance of semiconductor surfaces [5,6,7]. Within the last decade the use of M4PP metrology has broadened from development and process monitoring for tunnelling spin valves [8] to characterization of shallow semiconductor junctions [9].…”

Micro-four-point probe Hall effect measurement method

“…Four-point probes are widely used for sheet resistance characterization since essentially no additional sample preparation is necessary. 1 It has recently been shown that micro-four-point probes 3 are able to accurately measure sheet resistance of ultrashallow junctions with high spatial resolution 4 and without artifacts due to probe penetration 5 and leakage current; 6 moreover carrier profiling on beveled ultrashallow junctions has been demonstrated. 7,8 The implantation and annealing processes used in semiconductor fabrication today cannot guarantee 100% activation of the implanted dose, and defects not removed by annealing may lead to reduced carrier mobility.…”