ELASTIC-SCATTERING CORRECTIONS IN AES AND XPS .1. 2 RAPID MONTE-CARLO METHODS FOR CALCULATING THE DEPTH DISTRIBUTION FUNCTION

We present improvements to the Monte Carlo methods used to calculate emission depth distribution functions (DDFs), emission function decay lengths (EFDLs) and attenuation lengths in quantitative XPS and AES. These reduce the time required to reach any desired level of accuracy by a factor Of approximately 500, so that even a personal computer can produce accurate results in 2 or 3 min. These rapid results are due to the new technique of averaging over an ensemble of possible inelastic events for each feasible set of elastic scatterings in the Monte Carlo simulation, closely related to methods that have been used successfully in nuclear physics for many years. No new approximations are required. The results are compared with exact analytical solutions for simple special cases; agreement is excellent.