Sample rotation during depth profiling with secondary ion mass spectrometry

✍ Scribed by John J. Vajo; Eun-Hee Cirlin

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 809 KB
• Volume: 17
• Category: Article
• ISSN: 0142-2421
• DOI: 10.1002/sia.740171107

✦ Synopsis

Abstract

Depth profiles obtained using secondary ion mass spectrometry with O~2~^+^ primary ions and without sample rotation have been measured for Mg‐implanted GaAs, B‐ and ^2^H‐implanted bulk Mo, a deposited Ni/SiO~2~ interface and for a molecular‐beam‐epitaxy‐grown structure consisting of monolayers of AIAs in GaAs. For the Mg‐implanted GaAs sample profiled without rotation, secondary ion yield changes associated with the development of surface ripples distorted both the matrix an implant profiles. Rotation of the sample during profiling prevented the formation of; surface ripples and, therefore, the associated yield changes. For the bulk Mo sample, surface roughness developed for both rotated and stationary samples. However, with sample rotation, the roughness was considerable reduced and, consequently, depth resolution for the implant profiles was improved. Similarly, the resolution of the Ni/SiO~2~ interface was greatly increased using sample rotation. For the monolayer AIAs/GaAs sample, profiles were obtained with low primary ion primary ion energy and large angle of incidence with respect to the surface normal in order to optimize the depth resolution. Under these conditions without sample rotation, uneven sputtering by spatially averaging the ion current density, thereby providing good depth resolution of the AIAs monolayers almost without degradation.