Impact of hydrogen implantation on helium implantation induced defects

Silicon-based power device performances are largely affected by metal contamination occurring during device manufacturing. Among the usual gettering techniques, recent developments were done on high dose helium implantation. Even though the gettering efficiency of this technique has been demonstrated in device application, the required doses are still extremely high for an industrial application. Recently, it has been shown that the use of H/He co-implantation limits the total requested doses [1]. In this paper, co-implantation of H/He, which has been already used to reduce the dose in the smart-cut (R) process is explored. The goal of this work is to decrease efficiently the implanted dose maintaining an efficient metallic gettering without degrading the Si surface. The impact of H implantation on He implantation induced defects is carefully studied. The TEM observations have evidenced that hydrogen addition drastically modified the defect band structure and promotes the cavity growth. Additionally, we demonstrate that an efficient gettering can be obtained.