The Carbon Co-implant with Spike RTA Solution for Boron Extension
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0912-C01-03
The Carbon Co-implant with Spike RTA Solution for Boron Extension Bartek J. Pawlak1, Emmanuel Augendre2, Simone Severi2, Pierre Eyben2, Tom Janssens2, Annelies Falepin2, Philippe Absil2, Wilfried Vandervorst2, Susan Felch3, Erik Collart4, Robert Schreutelkamp5, and Nick Cowern6 1 Philips Research Europe, Kapeldreef 75, Leuven, B-3001, Belgium 2 IMEC, Leuven, B-3001, Belgium 3 AMAT, Sunnyvale, CA 94085 4 AMAT, Horsham, RH13 5PX, United Kingdom 5 AMAT, Leuven, B-3001, Belgium 6 University of Surrey, Surrey, GU2 7XH, United Kingdom ABSTRACT We present B junction extensions that are extremely abrupt and shallow manufactured by amorphization, C co-implantation and conventional rapid thermal annealing (RTA). Resulting junctions have abruptnesses of 2 nm/dec better than as-implanted profiles. The most shallow B junction that has been manufactured is 15 nm deep and Rs = 626 Ω/sq. Successful implementation of these junctions is straightforward for P-MOS 30 nm gate length devices.
INTRODUCTION Most junction formation technologies for 30 nm gate length transistors involve advanced annealing technologies, which are diffusion-less and produce very close to as-implanted dopant profiles. In our approach we extend the applicability of conventional RTA combined with amorphization and C or F co-implantation. In this way B can be shaped to obtain a box-like profile, which is very attractive for short channel transistors. Nonimpurity implantation has a strong impact on dopant profile by suppresion of B transient enhanced diffusion (TED) [1], its activation [2, 3] and introduces only minor modification in the complete transistor flow.
EXPERIMENTAL DETAILS Experiments were performed on 200 mm wafers for blanket and device experiments. Junctions were formed by amorphization with Ge and Si at an energies of 12-50 keV and doses 0.5-1 × 1015 at./cm2, co-implantation of C or F at energies 3-6 keV, and doses 0.5, 1, and 1.5 × 1015 at./cm2. Implant energies were used for B at 0.2 and 0.5 keV and dose 7 × 1014 at./cm2, using a tilt angle of 7° and a twist of 27° using an Applied Materials Quantum X® Implant system. Wafers were annealed in the Applied Materials RadiancePLUS™ RTP system at 1030, 1050, 1070 °C spike RTA. After processing the B depth profiles were measured by secondary ion mass spectroscopy (SIMS) using an Atomika 4500 instrument. The sheet resistance (Rs) measurements were performed using
a four-point probe on the SSM 240 instrument, with a probe penetration depth of 25 nm. For good Rs measurement reliability high resistive deep wells were used before wafers were processed to avoid conduction contribution from the substrate. In device experiments a conventional transistor processing flow has been applied to investigate the impact of amorphization and C co-implantation. Poly-Si gates with predoping are used. In order to investigate mechanisms of junction leakage some transistors did not have pocket implants to isolate the contribution of band-to-band tunneling from defect related mechanisms.
RESULTS AND DISCUSSION
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