COMPARISON BETWEEN COMPUTER-SIMULATION AND DIRECT SECONDARY-ION MASS-SPECTROMETRY MEASUREMENT OF LATERAL DOPANT DISTRIBUTIONS

A two-dimensional secondary ion mass spectrometry dopant profiling tec hnique, using a specially prepared sample, has been used to provide hi gh spatial resolution, high sensitivity, dopant maps of boron and arse nic. These have been compared with TSUPREM(IV) simulations. However, i nvestigation of the disagreements between the modeled and experimental data cannot be made, as a major problem has been accurately determini ng the position of the mask edge on the reconstructed profile. Previou s methods have introduced errors of up to 0.2 mum. This has been overc ome by using a low energy, low dose, germanium implant as a marker of the mask window. The effect of this marker implant on the dopant distr ibution to be measured has been investigated and estimates of the accu racy of locating the mask edge have been made using the TSUPREM(IV) co de. It is expected that the mask edge in later profiles will be locate d to better than 15 nm.