Steady-State Versus Rapid Thermal Annealing of Phosphorusimplanted Pseudomorphic Si(100)/Ge0.12Si0.88

1994 ◽  
Vol 342 ◽  
Author(s):  
D. Y. C. Lie ◽  
J. H. Song ◽  
N. D. Theodore ◽  
F. Eisen ◽  
M.-A. Nicolet ◽  
...  

ABSTRACTPseudomorphic Ge0.12Si0.88 films 265 nm thick grown by molecular beam epitaxy on p- Si(100) substrates were implanted with 100 keV 31P at room temperature for a dose of 5 x 1013/cm2. The projected range of the implanted P is about half the epilayer thickness. The implanted layers, together with non-implanted virgin samples, were subsequently annealed by both rapid thermal annealing in nitrogen and by steady-state furnace annealing in vacuum. The damage and strain of the annealed layers were studied by 4He channeling and x-ray doublecrystal diffraction. For a dose of 5 x 1013 P /cm2, both the damage and strain introduced by implantation can be completely removed, within instrumental sensitivity, by rapid thermal annealing at 700 °C for 10 - 40 s. Furnace annealing at 550 °C for 30 min for this sample removes most of the damage and strain induced by implantation. Furnace annealing at 700 °C or higher worsens the crystallinity of the layer and the strain relaxes. Hall measurements were performed on the same samples. Furnace annealing cannot achieve good dopant activation without introducing significant strain relaxation to the heterostructure, while rapid thermal annealing can.

1983 ◽  
Vol 23 ◽  
Author(s):  
D.L. Kwong ◽  
R. Kwor ◽  
B.Y. Tsaur ◽  
K. Daneshvar

ABSTRACTThe formation of composite TaSi2/n+ Poly-Si silicide films through the use of rapid thermal annealing (RTA) is investigated by x-ray diffraction, four point probe, scanning Auger microprobes (SAM) with ion sputter etching, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and capacitance-voltage (C-V) measurements. 0.2 μm polysilicon is deposited on oxidized Si wafer by LPCVD and doped with phosphorus. A layer of 2200 A TaSix is then co-sputtered on polysilicon samples from separate targets. These as-deposited films are then annealed by RTA in an argon ambient for 1 sec. and 10 sec. at various temperatures. X-ray diffraction and SAM results show the rapid formation of a uniform stoichiometric tantalum disilicide via Si migration from polysilicon. TEM micrographs show simlilar results for samples annealed at 1000°C in furnace for 30 min. or by RTA for 1 sec., exhibiting average grain size greater than 1000 A. Sheet resistance of samples annealed by furnace annealing and RTA are comparable. SEM micrographs indicate that the surface morphology of the RTA-annealed sample is superior to that obtained by furnace annealing. These results show that RTA may offer a practical solution to low-resistivity silicide formation in VLSI circuits.


1989 ◽  
Vol 146 ◽  
Author(s):  
Leonard Rubin ◽  
Nicole Herbots ◽  
JoAnne Gutierrez ◽  
David Hoffman ◽  
Di Ma

ABSTRACTA method for producing shallow silicided diodes for MOS devices (with junction depths of about 0.1 µm), by implanting after forming the silicide layer was investigated. The key to this integrated process is the use of rapid thermal annealing (RTA) to activate the dopants in the silicon, so that there is very little thermal broadening of the implant distribution. Self-aligned titanium silicide (TiSi2) films with thicknesses ranging from 40 to 80 nm were grown by RTA of sputter deposited titanium films on silicon substrates. After forming the TiSi2, arsenic and boron were implanted. A second RTA step was used after implantation to activate these dopants. It was found that implanting either dopant caused a sharp increase in the sheet resistivity of the TiSi2. The resistivity can be easily restored to its original value (about 18 µΩ-cm) by a post implant RTA anneal. RBS analysis showed that arsenic diffuses rapidly in the TiSi2 during RTA at temperatures as low as 600°C. SIMS data indicated that boron was not mobile up to temperatures of 900°C, possibly because it forms a compound with the titanium which precipitates in the TiSi 2. Coalescence of TiSi2 occurs during post implant furnace annealing, leading to an increase in the sheet resistivity. The amount of coalescence depends on the film thickness, but not on whether or not the film had been subject to implantation. Spreading resistance profiling data showed that both arsenic and boron diffused into the TiSi2 during furnace annealing, reducing the surface concentrations of dopant at the TiSi2/Si interface. Both N+/P and P+/N diodes formed by this technique exhibited low leakage currents after the second RTA anneal. This is attributed to removal of the implant damage by the RTA. In summary, the second RTA serves the dual purpose of removing implant damage in the TiSi2 and creating the shallow junction by dopant activation.


1994 ◽  
Vol 342 ◽  
Author(s):  
J.P. de Souza ◽  
P.F.P. Fichtner ◽  
D.K. Sadana

ABSTRACTCross section TEM and channeling analysis show that the heating rate (HR) of a rapid thermal annealing (RTA) cycle affects the residual defect distribution in Si implanted with As+ to a heavy dose (≈ 1016 cm−2). Two defect bands are observed after solid phase epitaxial growth (SPEG): the first one centered at a depth corresponding to the projected range of the As (band I), and the second one located at depth corresponding to the original amorphous crystalline (a-c) interface (band II). The density of defects in band I is found to increase with the As dose, and with the annealing temperature (550 - 650°C, furnace annealing). However, for RTA (800 - 1000°C) both the density and depth distribution of these defects are dependent on HR. We propose that Si self-interstitials (SiI) are created at the a-c interface when As becomes substitutional during SPEG. The SPEG velocity determines whether the SiI are accommodated in the amorphous Si layer (low velocities) or are captured by the regrowing c-Si (high velocities)


1994 ◽  
Vol 342 ◽  
Author(s):  
Jos G.E. Klappe ◽  
István Bársony ◽  
Pierre H. Woerlee ◽  
Tom W. Ryan ◽  
P. Alkemade

ABSTRACTIn this paper, low-energy (45 keV) implantations of phosphorous and boron into silicon were studied. A comparison of doping profiles, secondary defect formation, electrical activation and diode leakage was made between Rapid Thermal Annealing (RTA) and conventional furnace annealing. The samples were analysed by High-Resolution X-Ray Diffraction (HR-XRD), X-TEM, SIMS, spreading resistance (SRP) and sheet resistance measurements.The non-destructive HR-XRD technique combined with the novel simulation software was a very useful tool for the defect characterisation and for the choice of the optimum annealing temperature. Furthermore estimations of electrically active dopant atoms were made with HR-XRD by measurement of the strain. With RTA a substitutional dopant concentration of a factor 2 to 4 higher than with furnace annealing can be obtained, for P and B respectively. Electrical measurements show that not all of the substitutional dopants are electrically active, however. Thus estimates of the electrically active dopant atoms with HR-XRD require further study. Furthermore it appeared that RTA was superior to furnace anneal for lowering sheet resistances, defect removal and dopant profile broadening. However, furnace anneal gave the best results for diode leakage currents. This indicates that RTA processing needs to be further refined or that combined RTA/furnace processes need to be developed.


1995 ◽  
Vol 379 ◽  
Author(s):  
D.Y.C. Lie ◽  
J.H. Song ◽  
M.-A. Nicolet ◽  
N.D. Theodore ◽  
J. Candelaria ◽  
...  

ABSTRACTMetastable pseudomorphic GexSi1−x (x=8%,16%) films were deposited on p-Si(100) substrates by chemical-vapor-deposition and then implanted at room temperature with 90 keV arsenic ions to a dose of 1.5×1015/cm2. The implantation amorphizes approximately the top 125 nm of the 145 nm-thick GeSi layers. The Si-GeSi interfaces remain sharp after implantation. Implanted and non-implanted GeSi samples, together with implanted Si control samples, were subsequently annealed simultaneously by rapid thermal annealing in a nitrogen ambient at 600,700,800 × for 10,20,40s at each temperature. The implanted samples undergo layer-by-layer solid-phase epitaxial regrowth during annealing at or above 600 ×C. The amorphized and regrown GeSi layers are always fully relaxed with a very high density of dislocations (1010-1011/cm2). At a fixed annealing temperature, strain relaxation of an implanted GeSi film is substantially more extensive than that of a non-implanted one. About 50-90% of the implanted arsenic ions become electrically active after the completion of solid-phase epitaxy. The percentages of arsenic ions that are activated in the Si control samples are generally higher than those in GeSi. The room-temperature sheet electron mobility in GeSi is roughly 30% lower than that in Si for a given sheet electron concentration. We conclude that metastable GeSi on Si(100) amorphized by arsenic ions and recrystallized by solid-phase epitaxy cannot recover both its crystallinity and its pseudomorphic strain under rapid thermal annealing.


1993 ◽  
Vol 321 ◽  
Author(s):  
D. Y. C. Lie ◽  
T. K. Cams ◽  
N. D. Theodore ◽  
F. Eisen ◽  
M.-A. Nicolet ◽  
...  

AbstractA pseudomorphic Ge0.12Si0.88 film 265 nm thick grown on a Si (100) substrate by molecular beam epitaxy was implanted at room temperature with a dose of 1.5 × 1015 cm2 of 100 keV P ions. The projected range of the ions is about 125 nm, which is well within the film thickness. Only the top portion of the Ge0.12Si0.88 layer was amorphized by the implantation. Both implanted and non-implanted samples were subsequently annealed in vacuum for 30 Minutes from 400 °C to 800 °C. Values of electron Hall sheet mobility and concentration in the implanted Ge0.12Si0.88 epilayer were measured after annealing. The solid phase epitaxial regrowth is complete at 550 °C, where the implanted phosphorus reaches - 100 % activation. The regrown Ge0.12Si0.88 layer exhibits inferior crystalline quality to that of the virgin sample and is relaxed, but the non-implanted portion of the film remains pseudomorphic at 550 °C. When annealed at 800 °C, the strain in the whole epilayer relaxes. The sheet electron mobility values measured at room temperature in the regrown samples (Tann ≥ 550 °C) are about 20% less than those of pure Si.


1987 ◽  
Vol 92 ◽  
Author(s):  
E. Ma ◽  
M. Natan ◽  
B.S. Lim ◽  
M-A. Nicolet

ABSTRACTSilicide formation induced by rapid thermal annealing (RTA) and conventional furnace annealing (CFA) in bilayers of sequentially deposited films of amorphous silicon and polycrystalline Co or Ni is studied with RBS, X-ray diffraction and TEM. Particular attention is paid to the reliability of the RTA temperature measurements in the study of the growth kinetics of the first interfacial compound, Co2Si and Ni2Si, for both RTA and CFA. It is found that the same diffusion-controlled kinetics applies for the silicide formation by RTA in argon and CFA in vacuum with a common activation energy of 2.1+0.2eV for Co2Si and 1.3+0.2eV for Ni Si. Co and Ni atoms are the dominant diffusing species; during silicide formation by both RTA and CFA. The microstructures of the Ni-silicide formed by the two annealing techniques, however, differs considerably from each other, as revealed by cross-sectional TEM studies.


2011 ◽  
Vol 1321 ◽  
Author(s):  
A. Kumar ◽  
P.I. Widenborg ◽  
H. Hidayat ◽  
Qiu Zixuan ◽  
A.G. Aberle

ABSTRACTThe effect of the rapid thermal annealing (RTA) and hydrogenation step on the electronic properties of the n+ and p+ solid phase crystallized (SPC) poly-crystalline silicon (poly-Si) thin films was investigated using Hall effect measurements and four-point-probe measurements. Both the RTA and hydrogenation step were found to affect the electronic properties of doped poly-Si thin films. The RTA step was found to have the largest impact on the dopant activation and majority carrier mobility of the p+ SPC poly-Si thin films. A very high Hall mobility of 71 cm2/Vs for n+ poly-Si and 35 cm2/Vs for p+ poly-Si at the carrier concentration of 2×1019 cm-3 and 4.5×1019 cm-3, respectively, were obtained.


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