AVS 53rd International Symposium
    Manufacturing Science and Technology Thursday Sessions
       Session MS-ThA

Paper MS-ThA7
Leakage Current and Dopant Activation in Ultra-Shallow Junctions Following Ms-Anneals Measured by Non-Contact Junction Photo-Voltage Methods

Thursday, November 16, 2006, 4:00 pm, Room 2018

Session: Sensors, Metrology, and Control
Presenter: V.N. Faifer, Frontier Semiconductor
Authors: V.N. Faifer, Frontier Semiconductor
T.M.H. Wong, Frontier Semiconductor
M.I. Current, Frontier Semiconductor
Correspondent: Click to Email
Leakage current and dopant activation characteristics of ultra-shallow junctions formed with ms-timescale anneals, which provide the beneficial result of minimal dopant diffusion, are highly sensitive to damage accumulation effects during the implantation of dopants, pre-amorphizing and various cocktail (C, F, S, etc.) ions. Damage accumulation levels are a result of the choice of ion, energy, dose and target material as well as process conditions such as beam current density, wafer temperature and beam scanning details for each implant cycle. The residual damage levels after annealing depend on the depth and character of the accumulated damage and the time-at-temperature ramp and ambient atmosphere conditions during each annealing step. For ms-timescale anneals which involve the use of scanned and pulsed energy deposition, the uniformity of the dopant activation and damage annealing process is strongly dependent on the spatial extent and overlap strategies used for the energy deposition beam used for heating. Measurement of junction characteristics through analysis of surface photo-voltage levels provides non-contact, high precision and independent measures of sheet resistance and leakage current density over 4 orders of magnitude. Discussion of leakage current effects will include the impact of background doping and defect density on carrier recombination and trap-assisted tunneling mechanisms. High-resolution (1,000 points per wafer) mapping of sheet resistance and leakage current variations provides rapid feedback for process evaluation of implant and annealing process equipment and correlation of conditions which result in favorable dopant activation and damage annealing.