VERIFICATION OF LATERAL SECONDARY-ION MASS-SPECTROMETRY AS A METHOD FOR MEASURING LATERAL DOPANT DOSE DISTRIBUTIONS IN MICROELECTRONICS TEST STRUCTURES

''Lateral secondary ion mass spectrometry (SIMS)'' has been demonstrat ed to be capable, within certain limits, of measuring the lateral stra ggle and diffusion of dopants under mask edges. In the present work me asurements of lateral dose distributions of arsenic and boron in silic on are presented and discussed, and information on the error margins o f the method derived. It is shown that the lateral dose distribution o f arsenic and boron can be measured down to dose levels of 5 x 10(12) cm(-2) and 2.6 x 10(13) cm(-2), respectively. In repeated measurements , the profile shapes have been reproduced to within a few nanometers, and the profile position relative to the mask edge determined with abo ut +/-10 nm error, It is this rather high degree of accuracy that allo ws Lateral SIMS data to be of value in the calibration and validation of two-dimensional process simulators. An example is given showing the correlation between IMSIL (Technical University Vienna) simulation an d experimental data for an as-implanted sample. By comparing experimen tal data from samples after dopant diffusion and at several topography variants with TMA SUPREM4 simulation, it is shown that an accurate de termination of the topography of the implant window in the vicinity of the mask edge is an essential prerequisite of any simulator calibrati on. (C) 1998 American Vacuum Society.