Combination of germanium preamorphization and sub-keV boron implantation for source/drain extension of pMOSFETs

Extensibility of deep sub-keV boron implantation technology is experimentally demonstrated by detailed study on the dependence of acceleration energy germanium preamorphization implantation (Ge PAI). Short-channel effect is improved by using relatively low energy Ge PAI (<3 keV). However, the drive current decreases with decreasing acceleration energy of Ge PAI due to high sheet resistance of source/drain extension. It is found that the acceleration energy of Ge PAI should be optimized in response to boron acceleration energy to suppress boron dose loss and transient enhanced diffusion caused by the defects introduced by PAI itself.