AVS 58th Annual International Symposium and Exhibition
    Plasma Science and Technology Division Thursday Sessions
       Session PS-ThP

Paper PS-ThP27
Plasma-based Techniques for Doping Three-Dimensional Structures

Thursday, November 3, 2011, 6:00 pm, Room East Exhibit Hall

Session: Plasma Science and Technology Poster Session
Presenter: George Papasouliotis, Varian Semiconductor Equipment Associates, Inc.
Authors: G. Papasouliotis, Varian Semiconductor Equipment Associates, Inc.
K. Han, Varian Semiconductor Equipment Associates, Inc.
H. Persing, Varian Semiconductor Equipment Associates, Inc.
L. Godet, Varian Semiconductor Equipment Associates, Inc.
Correspondent: Click to Email
Increasingly stringent demands for maximum device speed and control of random dopant fluctuation effects dictate changes in device architecture, with FinFET adoption becoming a viable possibility for device scaling at and beyond the 15 nm technology mode. Three-dimensional architectures pose a fundamental challenge for traditional ion beam implant processes, since, depending on the aspect ratio of the structure, certain sections can be inaccessible to the dopant beam. Plasma immersion ion implantation (Plasma Doping), which has been adopted as an enabling, production-worthy technology in the ultra high dose and low voltage regime for advanced DRAM device nodes, can be an alternative capable of overcoming these limitations. In this work, experiments are carried out using a VIISta PLAD system, which uses an ICP source to generate a discharge and a series of negative dc voltage pulses applied to the substrate to accelerate ions towards it. Silicon trenches are implanted using an AsH3-containing gas mixture in the PLAD reactor. The presence and activation of the N-type dopant onto the #D structures are characterized by physical (Secondary Ion Mass Spectrometry, Transmission Electron Microscopy, Energy Dispersive X-ray spectroscopy) and electrical methods, and discussed in conjunction with analysis of the gas phase in the plasma chamber. Our experimental results indicate the occurrence of a combination of implant and ion assisted deposition processes. It is shown that balancing the constituents of a plasma doping process and plasma characteristics such as electron temperature and gas phase composition is required to allow dopant incorporation into sidewalls of 3D structures.