Two dimensional profiling of ultra-shallow implants using SIMS

The lateral spread of dopant under the implant mask edge and its behaviour during thermal processing is becoming increasingly important as device dimensions are reduced. Direct measurement of the distribution by high spatial resolution SIMS is not possible owing to the very few impurity atoms present in the analyte volume at junction concentrations. In this paper we describe a SIMS based technique, using a special sample structure, that may be used to access this information and discuss the instrumental requirements, resolution and detection limits, as well as presenting cross sectional dopant data.