Hydrogen-induced surface blistering of sample chuck materials in hydrogen plasma immersion ion implantation

Hydrogen plasma immersion ion implantation (PIII) coupled with ion cut is a n economical way to synthesize silicon-on-insulator wafers. In order to avo id premature surface blistering caused by the coalescence of hydrogen micro cavities, the implantation temperature must be low (< 300 degreesC), and sa mple cooling is usually required due to the high ion flux in hydrogen PIII. In addition, the entire sample chuck including the silicon wafer and all t he exposed surfaces are bombarded by ions and sputtered impurities from the sample holder can be reimplanted or deposited onto the silicon wafer. Idea lly, the problem can be solved if the sample chuck is made of silicon but e ngineering a silicon sample chuck with sufficient electrical conductivity a nd a cooling mechanism is very complicated. In addition, the hydrogen ions implanted into the exposed silicon chuck surface can cause surface blisteri ng and exfoliation similar to the silicon wafer. The silicon particles rele ased into the vacuum chamber will reduce the process yield. One practical a pproach is to engineer the sample chuck with stainless steel and then coat the surface with a material compatible with silicon. If the blistering resi stance of the coating is better and the lifetime of the coating is sufficie ntly long, periodic cleaning can ensure particle and contamination free ope ration. In this work, we investigate the blistering behavior of three such materials, single-crystal silicon, polycrystalline/amorphous silicon, and s ilicon dioxide. Our results show that silicon dioxide is the best candidate , followed by polysilicon. However, the insulating nature of silicon dioxid e must be considered. Our theoretical simulation results show that an oxide layer several micrometers thick will not affect the surface potential sign ificantly even at a relatively low bias voltage. (C) 2001 American Vacuum S ociety.