Varying implant dose rate for defect reduction in laser thermal processing

2001 ◽  
Vol 4 (4) ◽  
pp. 339-343 ◽  
Author(s):  
Heather Banisaukas ◽  
Kevin S Jones ◽  
Somit Talwar ◽  
Dan F Downey ◽  
Scott Falk
Keyword(s):  
Dose Rate ◽  
Thermal Processing ◽  
Defect Reduction ◽  
Laser Thermal Processing

Defect Reduction in Laser Thermal Processing

2000 ◽  
Vol 610 ◽  
Author(s):  
Heather Banisaukas ◽  
Kevin S. Jones ◽  
Somit Talwar ◽  
Scott Falk ◽  
Dan F. Downey
Keyword(s):  
Dose Rate ◽  
Thermal Processing ◽  
Defect Density ◽  
Solid Phase ◽  
Amorphous Layer ◽  
Beam Current ◽  
Interface Roughness ◽  
Molten Layer ◽  
Order Of Magnitude ◽  
Laser Thermal Processing

AbstractLaser thermal processing (LTP) of Si involves laser melting a preamorphized layer in order to activate dopants and create a low resistivity contact. Defects are often observed to form during the recrystallization of the molten layer. This work focuses on varying the implant conditions and the pre-LTP annealing conditions in an effort to reduce these defect concentrations. The effect of very low temperature anneals (VLTA) and varying dose rates on the amorphous/crystalline interface roughness prior to LTP and the defect density after LTP have been investigated. The amorphous layer was created by a 10 keV 1×1015/cm2 Si+ implant. VLTA were conducted in a nitrogen gas furnace at temperatures between 400°C and 450°C for times between 5 minutes and 60 minutes. These anneals were chosen to minimize recrystallization of the amorphous layer by solid phase epitaxial regrowth. Variation in the dose rate from 0.06 mA/cm2 to 0.48 mA/cm2 was achieved by changing the beam current in the ion implanter. High-resolution crosssectional transmission electron microscopy (HR-XTEM) was used to analyze the effect of the VLTA or dose rate on the amorphous/crystalline interface. Results show that the 400°C 60 minute VLTA or the 0.48 mA/cm2 dose rate reduced the roughness of the amorphous/crystalline interface from over 45Å to around 15Å. This reduction in amorphous/crystalline interface roughness prior to laser thermal processing results in a reduction in LTP recrystallization defects by as much as an order of magnitude.

Laser thermal processing for shallow junction and silicide formation

1998 ◽  
Author(s):  
Somit Talwar ◽  
Gaurav Verma ◽  
Kurt H. Weiner ◽  
Carol Gelatos
Keyword(s):  
Thermal Processing ◽  
Silicide Formation ◽  
Shallow Junction ◽  
Laser Thermal Processing

Effect of Laser Thermal Processing on Defect Evolution in Silicon

2002 ◽  
Vol 717 ◽  
Author(s):  
Erik Kuryliw ◽  
Kevin S. Jones ◽  
David Sing ◽  
Michael J. Rendon ◽  
Somit Talwar
Keyword(s):  
Point Defects ◽  
Thermal Processing ◽  
Defect Formation ◽  
Secondary Ion Mass Spectrometry ◽  
Laser Energy ◽  
Process Window ◽  
Loop Formation ◽  
Transmission Electron ◽  
Ultra Shallow Junctions ◽  
Laser Thermal Processing

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.

Laser thermal processing for ultra shallow junction formation: numerical simulation and comparison with experiments

2003 ◽  
Vol 208-209 ◽  
pp. 345-351 ◽  
Author(s):  
M. Hernandez ◽  
J. Venturini ◽  
D. Zahorski ◽  
J. Boulmer ◽  
D. Débarre ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Thermal Processing ◽  
Shallow Junction ◽  
Junction Formation ◽  
Laser Thermal Processing ◽  
Comparison With Experiments

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

2004 ◽  
Vol 95 (11) ◽  
pp. 6048-6053 ◽  
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

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

2002 ◽  
Vol 717 ◽  
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.

Formation of titanium silicide on narrow gates using laser thermal processing

2002 ◽  
Vol 49 (1) ◽  
pp. 42-47 ◽  
Author(s):  
G. Verma ◽  
C. Gelatos ◽  
S. Talwar ◽  
J.C. Bravman
Keyword(s):  
Thermal Processing ◽  
Titanium Silicide ◽  
Laser Thermal Processing

Reduction of carrier depletion in p/sup +/ polysilicon gates using laser thermal processing

2003 ◽  
Vol 24 (5) ◽  
pp. 360-362 ◽  
Author(s):  
Y.F. Chong ◽  
H.-J.L. Gossmann ◽  
M.O. Thompson ◽  
K.L. Pey ◽  
A.T.S. Wee ◽  
...  
Keyword(s):  
Thermal Processing ◽  
Laser Thermal Processing
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