Solid Phase Epitaxy of Implanted Si-Ge-C Alloys

1995 ◽  
Vol 388 ◽  
Author(s):  
Xiang Lu ◽  
Nathan W. Cheung

AbstractSi1-x-yGexCy/Si heterostuctures were formed on Si (100) surface by Ge and C implantation with a high dose rate MEtal - Vapor Vacuum arc (MEVVA) ion source and subsequent Solid Phase Epitaxy (SPE). after thermal annealing in the temperature range from 600 °C to 1200 °C, the implanted layer was studied using Rutherford Back-scattering Spectrometry (RBS), cross-sectional High Resolution Transmission Electron Microscopy (HRTEM) and fourbounce X-ray Diffraction (XRD) measurement. Due to the small lattice constant and wide bandgap of SiC, the incorporation of C into Si-Ge can provide a complementary material to Si-Ge for bandgap engineering of Si-based heterojunction structure. Polycrystals are formed at temperature at and below 1000 °C thermal growth, while single crystal epitaxial layer is formed at 1100 °C and beyond. XRD measurements near Si (004) peak confirm the compensation of the Si1-x Gex lattice mismatch strain by substitutional C. C implantation is also found to suppress the End of Range (EOR) defect growth.

1991 ◽  
Vol 235 ◽  
Author(s):  
Kin Man Yu ◽  
Ian G. Brown ◽  
Seongil Im

ABSTRACTWe have synthesized single crystal Si1−xGex alloy layers in Si <100> crystals by high dose Ge ion implantation and solid phase epitaxy. The implantation was performed using the metal vapor vacuum arc (Mevva) ion source. Ge ions at mean energies of 70 and 100 keV and with doses ranging from 1×1016 to to 7×1016 ions/cm2 were implanted into Si <100> crystals at room temperature, resulting in the formation of Si1−xGex alloy layers with peak Ge concentrations of 4 to 13 atomic %. Epitaxial regrowth of the amorphous layers was initiated by thermal annealing at temperatures higher than 500°C. The solid phase epitaxy process, the crystal quality, microstructures, interface morphology and defect structures were characterized by ion channeling and transmission electron microscopy. Compositionally graded single crystal Si1−xGex layers with full width at half maximum ∼100nm were formed under a ∼30nm Si layer after annealing at 600°C for 15 min. A high density of defects was found in the layers as well as in the substrate Si just below the original amorphous/crystalline interface. The concentration of these defects was significantly reduced after annealing at 900°C. The kinetics of the regrowth process, the crystalline quality of the alloy layers, the annealing characteristics of the defects, and the strains due to the lattice mismatch between the alloy and the substrate are discussed.


1990 ◽  
Vol 187 ◽  
Author(s):  
D. J. Howard ◽  
D. C. Paine ◽  
N. G. Stoffel

AbstractIn this paper we propose a new method for the synthesis of Si1−xGex strained-layer alloys using high-dose ion implantation of 74Ge at 200 keV into a preamorphized <001> Si wafer followed by solid phase epitaxy (SPE). Cross-sectional TEM was performed on samples at various stages of regrowth which revealed the evolution of the amorphous/crystalline interface and the development of strain relieving defects during SPE. We report that stacking faults are kinetically favored during SPE of Si1−xGex but are energetically feasible only above a critical strain energy. We propose a model that is based on the well known Matthews and Blakeslee approach which predicts the onset of stacking faults during SPE of high-dose ion implant-synthesized Si1−xGex/Si.


1998 ◽  
Vol 509 ◽  
Author(s):  
Dihu Chen ◽  
S. P. Wong ◽  
W.Y. Cheung ◽  
E.Z. Luo ◽  
W. Wu ◽  
...  

AbstractPlanar SiC/Si heterostructures were formed by high dose carbon implantation using a metal vapor vacuum arc ion source. The variations of the field emission properties with the implant dose and annealing conditions were studied. A remarkably low turn-on field of IV/μm was observed from a sample implanted at 35 keV to a dose of 1.0×1018 cm−2 with subsequent annealing in nitrogen at 1200°C for 2h. The chemical composition depth profiles were determined from x-ray photoelectron spectroscopy and the surface morphology was observed by atomic force microscopy. The formation of a thin surface stoichiometric SiC layer and the formation of densely distributed small protrusions on the surface are believed to be the two factors responsible for the efficient electron field emission.


2001 ◽  
Vol 680 ◽  
Author(s):  
D.H. Chen ◽  
S.P. Wong ◽  
J.K.N. Lindner

ABSTRACTThin SiC layers were synthesized by high dose C implantation into silicon using a metal vapor vacuum arc ion source at various conditions. Characterization of the ion beam synthesized SiC layers was performed using various techniques including x-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) absorption, and Raman spectroscopy. The XPS results showed that for samples with over-stoichiometric implant doses, if the implant beam current density was not high enough, even after prolonged thermal annealing at high temperatures, the as-implanted gaussian-like carbon depth profile remained unchanged. However, if the implant beam current density was sufficiently high, there was significant carbon redistribution during annealing, so that a thicker stoichiometric SiC layer can be formed after annealing. The XPS and Raman results also showed that there were carbon clusters formed in the as-implanted layers for the low beam current density implanted samples, while the formation of such carbon clusters was minimal in the high beam current density as-implanted samples. The effect of beam current density on the fraction of different bonding states of the implanted carbon atoms was studied.


1989 ◽  
Vol 147 ◽  
Author(s):  
K. M. Yu ◽  
B. Katz ◽  
I. C. Wu ◽  
I. G. Brown

AbstractWe have investigated the formation of IrSi3 layers buried in <111> silicon. The layers are formed by iridium ion implantation using a metal vapor vacuum arc (MEVVA) high current metal ion source at room temperature with average beam energy = 130 keV. Doses of the Ir ions ranging from 2×1016 to 1.5×1017/cm2 were implanted into <111> Si. The formation of IrSi3 phase is realized after annealing at temperatures as low as 500°C. A continuous IrSi3 layer of =200 Å thick buried under =400 Å Si was achieved with samples implanted with doses not less than 3.5×1016/cm2. Implantated doses above 8×1016/cm2 resulted in the formation of an IrSi3 layer on the surface due to excessive sputtering of Si by the TI ions. The effects of implant dose on phase formation, interface morphology and implanted atom redistribution are discussed. Radiation damage and regrowth of Si due to the implantation process was also studied.


1995 ◽  
Vol 396 ◽  
Author(s):  
Qicai Peng ◽  
S.P. Wong ◽  
J.B. Xu ◽  
I.H. Wilson

AbstractThe surface morphology of high dose Co implanted Si has been studied by atomic force microscopy. The Co implantation was performed using a metal vapor vacuum arc (MEVVA) ion source at an extraction voltage of 60 or 70 kV to a dose of 2×l017 or 4×l017 ions cm-2 at substrate temperatures Ts ranging from 210°C to 700°C. When Ts is less than about 600°C, the surface morphology of the implanted samples shows largely similar features of densely distributed narrow asperities. However, for the sample with Ts of 700°C, the surface morphology is significantly different and shows hillocks of much larger size. It is also found that when other parameters are fixed, for Ts less than about 600°C, the root-mean-square roughness Rrms increases exponentially with 7^, from the subnanometer scale to several nanometers. But for the sample with Ts of 700°C, there is an abrupt increase in Rrms to 35 nm. The variation of the surface morphology with other parameters is also discussed.


1995 ◽  
Vol 402 ◽  
Author(s):  
Qicai Peng ◽  
S. P. WONG

AbstractHigh dose Co implantation into Si has been performed with a metal vapor vacuum arc (MEVVA) ion source at an extraction voltage of 70 kV to doses from 8×1016 to 6×1017 ions cm−2 at substrate temperatures (Ts) in the range of 210°C to 700°C. Annealing was performed in nitrogen at various temperatures for various time intervals by either furnace annealing (FA) or rapid thermal annealing (RTA). The electrical properties of the CoSi2 layers formed were studied using resistivity and Hall effect measurements from 10 to 300K. We found that for all the samples prepared by MEVVA implantation, as long as a continuous CoSi2 layer was formed after annealing, a strong temperature dependence of the Hall coefficient was observed with a large peak at around 90 to 110K. The magnitude of the peak also varies depending on the substrate parameters and processing conditions. However, the temperature dependence of the resistivity for these CoSi2 layers follows the atthiessen's rule. We also found that it does not require high substrate temperature nor very high temperature annealing in order to form a CoSi2 layers with low resistivity by MEVVA implantation. Such low resistivity CoSi2 layers can be formed with a substrate temperature as low as 210°C after either RTA at high temperature for a few seconds or FA at a relatively low temperature of 750°C for one hour. The dependence of the electrical properties on Ts is also presented and discussed.


1985 ◽  
Vol 56 ◽  
Author(s):  
B.D. HUNT ◽  
N. LEWIS ◽  
E.L. HALL ◽  
L.G. JTURNER ◽  
L.J. SCHOWALTER ◽  
...  

AbstractThin (<200Å), epitaxial CoSi2 films have been grown on (111) Siwafers in a UHV system using a variety of growth techniques including solid phase epitaxy (SPE), reactive deposition epitaxy (RDE), and molecular beam epitaxy (MBE). SEN and TEN studies reveal significant variations in the epitaxial silicide surface morphology as a function of the sillciqd formation method. Pinhole densities are generally greater than 107 cm-2, although some reduction can be achieved by utilizing proper growth techniques. Si epilayers were deposited over the CoSi2 films inthe temperature range from 550ºC to 800ºC, and the reesuulttinng structures have been characterized using SEM, cross—sectional TEN, and ion channeling measurements. These measurements show that the Si epitaxial quality increases with growth temperature, although the average Si surface roughness and the CoSi2 pinhole density also increase as the growth temperature is raised.


1995 ◽  
Vol 402 ◽  
Author(s):  
G. Curello ◽  
R. Gwilliam ◽  
M. Harry ◽  
R. J. Wilson ◽  
B. J. Sealy ◽  
...  

AbstractIn this work iridium silicidation of high dose Ge+ implanted Si layers has been studied. Compositional graded SiGe layers with a Ge peak concentration between 6 at.% and 12 at.% have been fabricated using 200 keV Ge+ ion implantation into (100) Si. A 20 nm thick Ir film was then deposited by e-beam evaporation with thermal reaction being performed to both regrow the implantation damage and form the silicide. The crystal quality of the SiGe layer and its interaction with the Ir film have been studied by cross-sectional Transmission Electron Microscopy (XTEM) and Rutherford Backscattering Spectrometry (RBS).Solid Phase Epitaxial Growth (SPEG) in the low dose case has produced a defect free SiGe layer with the formation of the IrSi phase. The annealing ambient was found to be critical for the silicidation. For the high dose case, as expected, strain relaxation related defects were observed to nucleate at a depth close to the projected range of the Ge+ implant and to extend up to the surface. A second rapid thermal annealing at higher temperatures, performed in forming gas, consumed most of the defective layer moving the silicide interface closer to the peak of the Ge distribution. A second low dose Ge+ implant following the metal deposition has been found to have a beneficial effect on the quality of the final interface. An amorphizing 500 keV Si+ implant followed by SPEG has finally been used to move the end of range defects far from the interface.


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