Backside and frontside depth profiling of B delta doping, at low energy, using new and previous magnetic SIMS instruments

A sample, composed of inverted boron deltas/SiO2/boron deltas/silicon on an insulator substrate (SOI), was analyzed using a Cameca IMS 5f and a Cameca IMS Wf, with 500 eVO2þ, oxygen flooding, and an electron gun. To synthesize this ‘‘double delta doping’’ sample, two identical boron multi-deltas were grown on SOI wafers and molecularly bonded upside down, then one SOI substrate was removed. The quality of this sample was checked by TEM and AFM. From the boron deltas’ SIMS depth profiles, a comparative study of the two SIMS instruments was carried out by looking in detail at the depth resolution parameters. It was found that depth profiles acquired with both tools are very similar to those measured by TEM. Both tools separate B deltas 2 nm apart. However, the primary beam density is higher with the IMS Wf, allowing a two times faster analysis time than with the IMS 5f. This sample structure also allowed us to acquire in one measurement both the backside and the conventional front side depth profiles, therefore allowing the contribution from both the epitaxial growth and the contribution from the instrumental SIMS profiling conditions to be separated. # 2004 Elsevier B.V. All rights reserved.