Siamak Salimian

A plasma doping process for 3D finFET source/drain extensions

A conformal doping technique is demonstrated for 3D finFET source/drain extensions using a plasma doping (PLAD) system. The arsenic dopant distribution at the top and the sidewalls of the fin was characterized by Energy Dispersive X-Ray spectroscopy (EDS) mapping, EDS line scan, and through-fin secondary ion mass spectroscopy (SIMS). The residual post-anneal damage was also evaluated by cross-section transmission electron spectroscopy (X-TEM). The effects of energy, dose and other plasma doping parameters on the sidewall dopant distribution are also studied.

Plasma process optimization for N-type doping applications

Plasma doping (PLAD) has been adopted across the implant technology space and into high volume production for both conventional DRAM and NAND doping applications. PLAD has established itself as an alternative to traditional ion implantation by beamline implantation. The push for high doping concentration, shallow doping depth, and conformal doping capability expand the need for a PLAD solution to meet such requirements. The unique doping profile and doping characteristics at high dose rates allow for PLAD to deliver a high throughput, differentiated solution to meet the demand of evolving transistor technology. In the PLAD process, ions are accelerated to the wafer as with a negative wafer bias applied to the wafer. Competing mechanisms, such as deposition, sputtering, and etching inherent in plasma doping require unique control and process optimization. In this work, we look at the distinctive process tool control and characterization features which enable an optimized doping process using n-type (PH3 or...

Sidewall doping mechanism and doping profile tuning on 3D structure by plasma doping

In this paper the primary mechanisms for the plasma doping (PLAD) of 3D structures — direct implant, scattered implant, deposition & knock-in, and sputtering (etching) — are discussed. The TRI3DYN code was used to elucidate the roles these various doping mechanisms play. Through-fin SIMS profiles for an arsenic plasma doping process were calculated from the model and compared to experimental results. Further, by adjusting the competition and balance among these different doping mechanisms, we also demonstrate that the doping profile can be tuned on 3D fin structures for a boron plasma doping process.