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.

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.

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.

Study of the Effects of a Two-Step Anneal on the End of Range Defects in Silicon

2002 ◽  
Vol 717 ◽  
Author(s):  
Renata A. Camillo-Castillo ◽  
Kevin. S. Jones ◽  
Mark E. Law ◽  
Leonard M. Rubin
Keyword(s):  
Defect Density ◽  
Low Energy ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Extended Defect ◽  
Enhanced Diffusion ◽  
Interstitial Concentration ◽  
Transmission Electron ◽  
Concentration Peak ◽  
Scale Down

AbstractTransient enhanced diffusion (TED) is a challenge that the semi-conductor industry has been faced with for more than two decades. Numerous investigations have been conducted to better understand the mechanisms that govern this phenomenon, so that scale down can be acheived. {311} type defects and dislocation loops are known interstitial sources that drive TED and dopants such as B utilize these interstitials to diffuse throughout the Si lattice. It has been reported that a two-step anneal on Ge preamorphized Si with ultra-low energy B implants has resulted in shallower junction depths. This study examines whether the pre-anneal step has a measurable effect on the end of range defects. Si wafers were preamorphized with Ge at 10, 12, 15, 20 and 30keV at a dose of 1x1015cm-2 and subsequently implanted with 1x1015cm-2 1keV B. Furnace anneals were performed at 450, 550, 650 and 750°C; the samples were then subjected to a spike RTA at 950°C. The implant damage was analyzed using Quantitative Transmission Electron Microscopy (QTEM). At the low energy Ge preamorphization, little damage is observed. However at the higher energies the microstructure is populated with extended defects. The defects evolve into elongated loops as the preanneal temperature increases. Both the extended defect density and the trapped interstitial concentration peak at a preanneal temperature of 550°C, suggesting that this may be an optimal condition for trapping interstitials.

Effect of Thermal ramping rate on defect formation in oxygen-implanted silicon-on-insulator material

1992 ◽  
Vol 50 (2) ◽  
pp. 1400-1401
Author(s):  
Ju-Chul Park ◽  
Stephen Krause ◽  
Mohammed El-Ghor
Keyword(s):  
Integrated Circuits ◽  
Cross Sections ◽  
Defect Formation ◽  
Semiconductor Device ◽  
Defect Density ◽  
Silicon On Insulator ◽  
High Dose ◽  
Ramp Rate ◽  
Rapid Thermal Anneal ◽  
Temperature Capability

Integrated circuits on SIMOX (Separation by IMplantation of OXygen) have higher speed, radiation hardness, and higher temperature capability. Defects in the top Si layer inhibit bipolar applications and may affect CMOS(Complementary Metal-On-Semiconductor) device yield, operation and reliability. As-implanted SIMOX has many types of defects, including short stacking faults(SFs), multiply faulted defects(MFDs), and {113} defects. In annealed SIMOX, new defects form during the ramping cycle. The effect of thermal ramping rate on the development of new defects has received only limited study. In this work, the effects of rapid thermal annealing(RTA) and thermal ramp rate on defect density and structural change were studied.Two set of samples were prepared with different oxygen doses. First, one set of (100) Si wafers was implanted with a high dose of 1.8×l018cm−2 at 200 KeV at 620°C. A rapid thermal anneal(RTA) wafer was obtained from a lamp anneal for 1 minute at 1320°C using a ramp rate of 50°C/sec. A portion of this sample was then conventionally annealed in a tube furnace for 5 hours at 1320°C. Another set of (100) Si wafers was implanted with a low dose of 3×l015cm−2 at 25°C. Different samples were then annealed at 1250°C for 30 sec using three ramp rates of 50°C/sec, l°C/sec and 0.1°C/sec. Cross-sections of the samples were studied with conventional transmission electron microscopy (CTEM) at 200 KeV.

Effect of Intermediate Thermal Processing on Microstructural Changes of Oxygen Implanted Silicon-on-Insulator Material

1991 ◽  
Vol 235 ◽  
Author(s):  
J. D. Lee ◽  
J. C. Park ◽  
S. J. Krause ◽  
P. Roitman ◽  
M. K. El-Ghor
Keyword(s):  
Thermal Processing ◽  
Defect Density ◽  
Silicon On Insulator ◽  
Ramp Rate ◽  
Microstructural Changes ◽  
Transmission Electron ◽  
Final Microstructure ◽  
Processing Steps ◽  
Very High ◽  
Material Form

ABSTRACTThe microstructural changes in oxygen implanted silicon-on-insulator material (SIMOX) at intermediate annealing steps and the changes by rapid thermal annealing (RTA) were studied with transmission electron microscopy. Defects found in as-implanted SIMOX, including multiply faulted defects, short stacking faults, and {113} defects, were all removed in anneals from 900°C to 1100°C. The threading dislocations in annealed material form at these temperatures during thermal ramping. RTA shows that the microstructure is significantly influenced by the ramp rate. The very high ramp rate in RTA results in very flat interfaces and a buried oxide layer with no Si islands, but significantly increases the defect density. Overall, the results show that intermediate thermal processing steps strongly affect the final microstructure of SIMOX material.

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.

Effect of Fabrication Variables on the Performance of Zinc Oxide Metal-Semiconductor-Metal Photodetectors

2007 ◽  
Vol 1035 ◽  
Author(s):  
Tingfang Yen ◽  
Dave Strome ◽  
Sung Jin Kim ◽  
Michael DiNezzaa ◽  
Alexander N. Cartwright ◽  
...  
Keyword(s):  
Laser Annealing ◽  
Zno Thin Films ◽  
Silicon Substrates ◽  
Radio Frequency Magnetron Sputtering ◽  
Rapid Thermal Anneal ◽  
Conventional Furnace ◽  
Metal Semiconductor Metal ◽  
Laser Anneal ◽  
Parallel Pattern ◽  
Msm Photodetectors

AbstractThe performance of ZnO metal-semiconductor-metal (MSM) photodetectors can be significantly influenced by modifications in the fabrication process. ZnO thin films were deposited onto silicon substrates by radio frequency magnetron sputtering and later annealed by conventional furnace, rapid thermal anneal or laser anneal. The photoluminescence (PL) analysis revealed that laser annealing at 250 mW/cm2 increased the 370 nm peak from 520 to 1700 a.u. and reduced the defect peak from 380 to 20 a.u. MSM photodetectors were fabricated using an interdigitated and parallel pattern. Values of current responsivity ranged from about 0.025 A/W to above 430 A/W depending upon fabrication conditions and design.

Control of transient enhanced diffusion of boron after laser thermal processing of preamorphized silicon

2002 ◽  
Vol 92 (3) ◽  
pp. 1344-1350 ◽  
Author(s):  
Y. F. Chong ◽  
K. L. Pey ◽  
A. T. S. Wee ◽  
T. Osipowicz ◽  
A. See ◽  
...  
Keyword(s):  
Thermal Processing ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Laser Thermal Processing

Transient enhanced diffusion after laser thermal processing of ion implanted silicon

1999 ◽  
Vol 75 (23) ◽  
pp. 3659-3661 ◽  
Author(s):  
Kevin S. Jones ◽  
Heather Banisaukas ◽  
Josh Glassberg ◽  
Ebrahim Andideh ◽  
Craig Jasper ◽  
...  
Keyword(s):  
Thermal Processing ◽  
Enhanced Diffusion ◽  
Transient Enhanced Diffusion ◽  
Laser Thermal Processing ◽  
Ion Implanted

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
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