Laser Thermal Processing of Alternate Dopants in Silicon

2002 ◽  
Vol 717 ◽  
Author(s):  
Mark H. Clark ◽  
Kevin S. Jones ◽  
Michael Rendon ◽  
Kevin A. Gable
Keyword(s):  
Laser Pulse ◽  
Carrier Concentration ◽  
Thermal Processing ◽  
Solid Solubility ◽  
Amorphous Layer ◽  
Rapid Thermal Anneal ◽  
Background Doping ◽  
Laser Thermal Processing ◽  
P Type ◽  
Doping Type

AbstractTraditionally, the choice of dopant has been limited to those species with the highest solid-solubility, however, Laser Thermal Processing (LTP) is not fundamentally limited by solid-solubility. Therefore, it is of interest to evaluate alternate dopants that have previously been excluded due to low solid-solubility. To this end, alternate dopants of 14N, 121Sb (n-type), 27Al, 70Ga, and 115In (p-type) are compared to conventional dopants of As and B respectively, after LTP and post-LTP thermal processing. Dopants were implanted into <100> silicon wafers of opposite background doping type that had previously been amorphized to a depth of approximately 300 angstroms by a 15 keV 28Si+ implant of 1x1015/cm2 dose. An implant energy of 5 keV was sufficiently low to confine the implanted ions to the amorphous layer, with the exception of B, which required an energy of 2 keV. All species were implanted at doses of 1x1014, 5x1014 and 1.5x1015/cm2. Samples were LTP utilizing a 308 nm, 18 ns laser pulse with a fluence of 0.680 J/cm2. Post-LTP thermal processing of the samples consisted of a 900 °C rapid thermal anneal (RTA) in a nitrogen ambient for a duration ranging from spike to 300 seconds. Measurements of the sheet resistance, mobility and carrier concentration were taken after both LTP, and the post-LTP thermal processing. Experimental results show that LTP of alternate dopants increases the electrically active carrier concentration of Ga, Al and Sb above solid-solubility. Additionally, the amount of deactivation upon post- LTP thermal processing depends on the alternate dopant species.

Effects of Nonmelt Laser Annealing on a 5keV Boron Implant in Silicon

2000 ◽  
Vol 610 ◽  
Author(s):  
Susan Earles ◽  
Mark Law ◽  
Kevin Jones ◽  
Rich Brindos ◽  
omit Talwar
Keyword(s):  
Thermal Processing ◽  
Laser Annealing ◽  
Defect Density ◽  
Ramp Rate ◽  
Rapid Thermal Anneal ◽  
Extended Defect ◽  
Enhanced Diffusion ◽  
Post Annealing ◽  
Laser Anneal ◽  
Laser Thermal Processing

AbstractTo investigate the effects of ramp rate on the transient enhanced diffusion of boron in silicon, laser thermal processing (LTP) in the nonmelt regime has been investigated. A nonmelt laser anneal has been performed on a 5 keV, 1e15 boron implant. The implant energy of 5keV was chosen to simplify analysis. A rapid thermal anneal (RTA) at 1000°C and furnace anneals at 750 °C were used to show the effect of post annealing on the LTPd samples. Results show the sheet resistance drops by up to a factor of two for samples receiving the nonmelt LTP and the RTA compared with the samples just receiving the RTA. An increase in the hall mobility was also observed for the samples receiving the LTP. The nonmelt LTP was also shown to strongly affect the extended defect density. During post anneals, a higher density of smaller defects evolved in the samples receiving the LTP.

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.

Excimer laser thermal processing of ultra-shallow junction: laser pulse duration

2004 ◽  
Vol 453-454 ◽  
pp. 145-149 ◽  
Author(s):  
J. Venturini ◽  
M. Hernandez ◽  
G. Kerrien ◽  
C. Laviron ◽  
D. Camel ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Pulse Duration ◽  
Excimer Laser ◽  
Thermal Processing ◽  
Laser Pulse Duration ◽  
Shallow Junction ◽  
Laser Thermal Processing ◽  
Junction Laser

Nucleation of Internal Melt During Pulsed Laser Irradiation

1985 ◽  
Vol 51 ◽  
Author(s):  
P. S. Peercy ◽  
Michael O. Thompson ◽  
J. Y. Tsao ◽  
J. M. Poate
Keyword(s):  
Laser Pulse ◽  
Laser Irradiation ◽  
Layer Thickness ◽  
Solid Solubility ◽  
Pulsed Laser ◽  
Amorphous Layer ◽  
Molten Layer ◽  
Simultaneous Measurements ◽  
Melt Duration ◽  
Pulsed Laser Irradiation

ABSTRACTReal-time measurements of the molten layer thickness and simultaneous measurements of the melt duration at the surface reveal that melt nucleates internally when Si implanted with low solid-solubility impurities such as In is melted with a 30 nsec laser pulse at 694 nm. Internal nucleation of melt was observed for all energy densities examined. Furthermore, at energy densities insufficient to melt the entire amorphous layer, internal nucleation of melt is followed by an explosive-like process in which a buried molten layer propagates toward the irradiated surface.

Effect of Cu doping on the electrical Properties of ZnTe by Vacuum Thermal Evaporation

2018 ◽  
Vol 31 (3) ◽  
pp. 20
Author(s):  
Sarmad M. M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Hall Effect ◽  
Carrier Concentration ◽  
Hall Mobility ◽  
Cu Doping ◽  
Before And After ◽  
Hall Effect Measurements ◽  
Evaporation Technique ◽  
P Type

In this study, the ZnTe thin films were deposited on a glass substrate at a thickness of 400nm using vacuum evaporation technique (2×10-5mbar) at RT. Electrical conductivity and Hall effect measurements have been investigated as a function of variation of the doping ratios (3,5,7%) of the Cu element on the thin ZnTe films. The temperature range of (25-200°C) is to record the electrical conductivity values. The results of the films have two types of transport mechanisms of free carriers with two values of activation energy (Ea1, Ea2), expect 3% Cu. The activation energy (Ea1) increased from 29meV to 157meV before and after doping (Cu at 5%) respectively. The results of Hall effect measurements of ZnTe , ZnTe:Cu films show that all films were (p-type), the carrier concentration (1.1×1020 m-3) , Hall mobility (0.464m2/V.s) for pure ZnTe film, increases the carrier concentration (6.3×1021m-3) Hall mobility (2m2/V.s) for doping (Cu at 3%) film, but  decreases by increasing Cu concentration.

Timing Sensitivity Analysis of Logical Nodes in Scan Design Integrated Circuits by Pulsed Diode Laser Stimulation

2008 ◽  
Author(s):  
T. Kiyan ◽  
C. Boit ◽  
C. Brillert
Keyword(s):  
Laser Pulse ◽  
Integrated Circuits ◽  
Continuous Wave ◽  
Fault Injection ◽  
Scan Design ◽  
Flip Flop ◽  
Laser Stimulation ◽  
Scan Chain ◽  
P Type ◽  
Scan Pattern

Abstract In this paper, a methodology based upon laser stimulation and a comparison of continuous wave and pulsed laser operation will be presented that localizes the fault relevant sites in a fully functional scan chain cell. The technique uses a laser incident from the backside to inject soft faults into internal nodes of a master-slave scan flip-flop in consequence of localized photocurrent. Depending on the illuminated type of the transistors (n- or p-type), injection of a logic ‘0’ or ‘1’ into the master or the slave stage of a flip-flop takes place. The laser pulse is externally triggered and can easily be shifted to various time slots in reference to clock and scan pattern. This feature of the laser diode allows triggering the laser pulse on the rising or the falling edge of the clock. Therefore, it is possible to choose the stage of the flip-flop in which the fault injection should occur. It is also demonstrated that the technique is able to identify the most sensitive signal condition for fault injection with a better time resolution than the pulse width of the laser, a significant improvement for failure analysis of integrated circuits.

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
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