Laser thermal processing for shallow junction and silicide formation

AbstractLaser Thermal Processing (LTP) involves laser melting of an implantation induced preamorphized layer to form highly doped ultra shallow junctions in silicon. In theory, a large number of interstitials remain in the end of range (EOR) just below the laser-formed junction. There is also the possibility of quenching in point defects during the liquid phase epitaxial regrowth of the melt region. Since post processing anneals are inevitable, it is necessary to understand both the behavior of these interstitials and the nature of point defects in the recrystallized-melt region since they can directly affect deactivation and enhanced diffusion. In this study, an amorphizing 15 keV 1 x 1015/cm2 Si+ implant was done followed by a 1 keV 1 x 1014/cm2 B+ implant. The surface was then laser melted at energy densities between 0.74 and 0.9 J/cm2 using a 308 nm excimer-laser. It was found that laser energy densities above 0.81 J/cm2 melted past the amorphous-crystalline interface. Post-LTP furnace anneals were performed at 750°C for 2 and 4 hours. Transmission electron microscopy was used to analyze the defect formation after LTP and following furnace anneals. Secondary ion mass spectrometry measured the initial and final boron profiles. It was observed that increasing the laser energy density led to increased dislocation loop formation and increased diffusion after the furnace anneal. A maximum loop density and diffusion was observed at the end of the process window, suggesting a correlation between the crystallization defects and the interstitial evolution.

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Ni Silicide Formation on Polycrystalline SiGe and SiGeC Layers

MRS Proceedings ◽

10.1557/proc-745-n4.8 ◽

2002 ◽

Vol 745 ◽

Cited By ~ 2

Author(s):

Erik Haralson ◽

Tobias Jarmar ◽

Johan Seger ◽

Henry H. Radamson ◽

Shi-Li Zhang ◽

...

Keyword(s):

Thin Film ◽

Thermal Processing ◽

Rapid Thermal Processing ◽

Lateral Diffusion ◽

Lateral Growth ◽

Silicide Formation ◽

Diffusion Couples ◽

Planar Configuration ◽

20 Nm

ABSTRACTThe reactions of Ni with polycrystalline Si, Si0.82Ge0.18 and Si0.818Ge0.18C0.002 films in two different configurations during rapid thermal processing were studied. For the usually studied planar configuration with 20 nm thick Ni on 130–290 nm thick Si1-x-yGexCy, NiSi1-xGex(C) forms at 450°C on either Si0.82Ge0.18 or Si0.818Ge0.18C0.002, comparable to NiSi formed on Si. However, the agglomeration of NiSi1-xGex(C) on Si0.818Ge0.18C0.002 occurs at 625°C, about 50°C higher than that of NiSi1-xGex on Si0.82Ge0.18. For thin-film lateral diffusion couples, a 200-nm thick Ni film was in contact with 80–130 nm thick Si1-x-yGexCy through 1–10 μm sized contact openings in a 170 nm thick SiO2 isolation. While the Ni3Si phase was formed for both the Si0.82Ge0.18 and Si0.818Ge0.18C0.002 samples, the presence of 0.2 at.% C caused a slightly slower lateral growth.

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Low temperature shallow junction formation using vacuum ultraviolet photons during rapid thermal processing

Applied Physics Letters ◽

10.1063/1.118674 ◽

1997 ◽

Vol 70 (13) ◽

pp. 1700-1702 ◽

Cited By ~ 15

Author(s):

R. Singh ◽

K. C. Cherukuri ◽

L. Vedula ◽

A. Rohatgi ◽

S. Narayanan

Keyword(s):

Low Temperature ◽

Thermal Processing ◽

Vacuum Ultraviolet ◽

Rapid Thermal Processing ◽

Shallow Junction ◽

Junction Formation ◽

Ultraviolet Photons

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Time-resolved reflectance studies of silicon during laser thermal processing of amorphous silicon gates on ultrathin gate oxides

Journal of Applied Physics ◽

10.1063/1.1719267 ◽

2004 ◽

Vol 95 (11) ◽

pp. 6048-6053 ◽

Cited By ~ 2

Author(s):

Y. F. Chong ◽

H.-J. L. Gossmann ◽

M. O. Thompson ◽

S. Yang ◽

K. L. Pey ◽

...

Keyword(s):

Amorphous Silicon ◽

Thermal Processing ◽

Gate Oxides ◽

Time Resolved ◽

Laser Thermal Processing

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Electrical and Structural Characterization of Boron Implanted Silicon Following Laser Thermal Processing

MRS Proceedings ◽

10.1557/proc-717-c1.10 ◽

2002 ◽

Vol 717 ◽

Cited By ~ 2

Author(s):

K. A. Gable ◽

K. S. Jones ◽

M. E. Law ◽

L. S. Robertson ◽

S. Talwar

Keyword(s):

Melting Temperature ◽

Thermal Processing ◽

Laser Annealing ◽

Substrate Surface ◽

Surface Region ◽

Process Window ◽

Near Surface ◽

Dopant Activation ◽

Transmission Electron ◽

Laser Thermal Processing

AbstractOne alternative to conventional rapid thermal annealing (RTA) of implants for ultra-shallow junction formation is that of laser annealing. Laser thermal processing (LTP) incorporates an excimer pulsed laser capable of melting the near surface region of the silicon (Si) substrate. The melt depth is dependent upon the energy density supplied by the irradiation source and the melting temperature of the substrate surface. A process window associated with this technique is able to produce similar junction depths over a range of energy densities due to the melting temperature depression established with pre-amorphization of the substrate surface prior to dopant incorporation. The process window of germanium (Ge) preamorphized, boron (B) doped Si was investigated. 200 mm (100) n-type Si wafers were preamorphized via 18 keV Ge+ implantation to 1x1015/cm2 and subsequently implanted with 1 keV B+ to doses of 1x1015/cm2, 3x1015/cm2, 6x1015/cm2, and 9x1015/cm2. The wafers were laser annealed from 0.50 J/cm2 to 0.88 J/cm2 using a 308 nm XeCl excimer irradiation source. Transmission electron microscopy (TEM) was used to determine the process window for each implant condition, and correlations between process window translation and impurity concentration were made. Four-point probe quantified dopant activation and subsequent deactivation upon post-LTP furnace annealing.

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