共查询到20条相似文献,搜索用时 15 毫秒
1.
E. D. Jones J. C. Clark J. Malzbender J. B. Mullin N. Shaw A. W. Brinkman 《Journal of Electronic Materials》1995,24(5):581-585
Studies on the diffusion of iodine and zinc into CdTe are reported. Each iodine profile was divided up into four distinct
regions and described mathematically by a function consisting of the sum of four complementary error functions. When plotted
on an Arrhenius graph, the diffusivities gave four straight line relationships with similar slopes and the Arrhenius parameters
for the fastest component of D01 = (7 ±3). 10-11 cm2 s-1 and E1 = (0.21 ±0.05) eV. When extrapolated down to 20°C this gave a diffusivity of 10-14 cm2 s-1 indicating that when iodine is diffused from the vapor it is not suitable as a long term stable dopant in devices where sharp
impurity profiles are required. In the case of the zinc diffusions, each profile can be divided into two parts and was fitted
satisfactorily by the sum of two complementary error functions giving two values of the diffusivities: Dslow due to zinc diffusion into the slice from the vapor and Dfast due to interdiffusion between a surface layer of Znx Cd1-x Te formed on the slice and the remaining CdTe. 相似文献
2.
V. Yu. Davydov V. V. Lundin A. N. Smirnov N. A. Sobolev A. S. Usikov A. M. Emel’yanov M. I. Makoviichuk E. O. Parshin 《Semiconductors》1999,33(1):1-5
The influence of rapid-anneal conditions and subsequent coimplantation of oxygen ions on the photoluminescence of erbium ions
implanted with an energy of 1 MeV and dose of 5×1014 cm−2 in MOCVD-grown GaN films is investigated. The erbium photoluminescence intensity at a wavelength ∼ 1.54 μm increases as the
fixed-time (15 s) anneal temperature is raised from 700 °C to 1300 °C. The erbium photoluminescence intensity can be increased
by the coimplantation of oxygen ions at anneal temperatures in the indicated range below 900 °C. The transformation of the
crystal structure of the samples as a result of erbium-ion implantation and subsequent anneals is investigated by Raman spectroscopy.
Fiz. Tekh. Poluprovodn. 33, 3–8 (January 1999) 相似文献
3.
Rapid thermal annealing of ion implantedn-type CdTe has been investigated. Samples were implanted with 60 keV Ar+ and As+ ions to a dose of 1 × 1014 cm−2 and subjected to anneal sequences of 5-100s at temperatures of 350-650° C. Photoluminescence measurements have indicated
that the implantation completely quenches the photoluminescence; however, anneals for only 5s at 350° C are sufficient to
recover most of the features of the photoluminescence spectrum to that equivalent of unimplanted material. Luminescence spectral
features associated with thermal annealing damage and substitutional As in inferred. Type conversion of the As+ implanted layer is observed and it has been shown that good diodes can be made, with the best behaviour resulting from a
5s anneal at 450° C.
Research supported by the Natural Sciences and Engineering Research Council of Canada 相似文献
4.
Mulpuri V. Rao Sadanand M. Gulwadi Phillip E. Thompson Ayub Fathimulla Olaleye A. Aina 《Journal of Electronic Materials》1989,18(2):131-136
Halogen lamp rapid thermal annealing was used to activate 100 keV Si and 50 keV Be implants in In0.53Ga0.47As for doses ranging between 5 × 1012−4 × 1014 cm−2. Anneals were performed at different temperatures and time durations. Close to one hundred percent activation was obtained
for the 4.1 × 1013 cm−2 Si-implant, using an 850° C/5 s anneal. Si in-diffusion was not observed for the rapid thermal annealing temperatures and
times used in this study. For the 5 × 1013 cm−2 Be-implant, a maximum activation of 56% was measured. Be-implant depth profiles matched closely with gaussian profiles predicted
by LSS theory for the 800° C/5 s anneals. Peak carrier concentrations of 1.7 × 1019 and 4 × 1018 cm−3 were achieved for the 4 × 1014 cm−2 Si and Be implants, respectively. For comparison, furnace anneals were also performed for all doses. 相似文献
5.
T. Alzanki R. Gwilliam N. G. Emerson B. J. Sealy 《Journal of Electronic Materials》2004,33(7):767-769
It is shown for the first time that antimony-implanted silicon produces the highest electrical activation (90%) with low resistivity
(<200 ohms/square) following low-temperature processing. Thus, annealing at 650°C produces the best results for antimony,
whereas for arsenic, it is necessary to anneal at temperatures above 1000°C to get optimum results. Silicon was implanted
with antimony at 12 keV and 40 keV and doses of 8.5×1014 cm−2 and 4×1014 cm−2, respectively, and arsenic at equivalent energies and doses. The electrical data from both implants are compared in order
to identify the process conditions require to obtain optimum results. It is demonstrated that annealing below 800°C produces
electrical profiles with no measurable diffusion of the antimony, but higher temperature anneals produce significant diffusional
broadening. 相似文献
6.
Boron implanted into n-type Si at 1015 cm−2 dose and energies from 500 eV to 1 keV was activated by annealing in nominally pure N2 and in N2 with small admixtures of O2. Effective process times and temperatures were derived by thermal activation analysis of various heating cycles. The lowest
thermal budgets used “spike anneals” with heating rates up to 150°C/sec, cooling rates up to 80°C/sec, and minimal dwell time
at the maximum temperature. Dopant activation was determined by sheet electrical transport measurements. Surface oxidation
was characterized by film thickness ellipsometry. P-n junction depths were inferred from analysis of sheet electrical transport
measurements and secondary ion mass spectroscopy profiles. Boron activation increases with boron diffusion from the implanted
region. Electrical activation has a thermal activation energy near 5 eV, while boron diffusion has an activation energy near
4 eV. Surface oxide can retard boron diffusion into the ambient for high-temperature anneals. 相似文献
7.
Nadeemullah Mahadik Mulpuri V. Rao Albert V. Davydov 《Journal of Electronic Materials》2006,35(11):2035-2040
The performance of a novel Ge/Cu/Ti metallization scheme on n-type GaN has been investigated for obtaining thermally and electrically
stable low-resistance ohmic contacts. Isochronal (2 min.) anneals in the 600–740°C temperature range and isothermal (690°C)
anneals for 2–10 min. duration were performed in inert atmosphere. For the 690°C isothermal schedule, ohmic behavior was observed
after annealing for 3 min. or longer with a lowest contact resistivity of 9.1 × 10−5 Ωcm2 after the 10 min. anneal for a net donor doping concentration of 9.2 × 1017 cm−Ω3. Mean roughness (Ra) for anneals at 690°C was almost constant at around 5 nm, up to an annealing duration of 10 min., which indicates a good
thermal stability of the contact scheme. 相似文献
8.
G. A. Kachurin A. F. Leier K. S. Zhuravlev I. E. Tyschenko A. K. Gutakovskii V. A. Volodin W. Skorupa R. A. Yankov 《Semiconductors》1998,32(11):1222-1228
This paper discusses the photoluminescence spectra of 500-nm-thick layers of SiO2 implanted with Si ions at doses of 1.6×1016, 4×1016, and 1.6×1017 cm−2 and then annealed in the steady-state region (30 min) and pulsed regime (1 s and 20 ms). Structural changes were monitored
by high-resolution electron microscopy and Raman scattering. It was found that when the ion dose was decreased from 4×1016 cm−2 to 1.6×1016 cm−2, generation of centers that luminesce weakly in the visible ceased. Moreover, subsequent anneals no longer led to the formation
of silicon nanocrystallites or centers that luminesce strongly in the infrared. Annealing after heavy ion doses affected the
photoluminescence spectrum in the following ways, depending on the anneal temperature: growth (up to ∼700 °C), quenching (at
800–900 °C), and the appearance of a very intense photoluminescence band near 820 nm (at >900 °C). The last stage corresponds
to the appearance of Si nanocrystallites. The dose dependence is explained by a loss of stability brought on by segregation
of Si from SiO2 and interactions between the excess Si atoms, which form percolation clusters. At low heating levels, the distinctive features
of the anneals originate predominantly with the percolation Si clusters; above ∼700 °C these clusters are converted into amorphous
Si-phase nanoprecipitates, which emit no photoluminescence. At temperatures above 900 °C the Si nanocrystallites that form
emit in a strong luminescence band because of the quantum-well effect. The difference between the rates of percolation and
conversion of the clusters into nanoprecipitates allows the precipitation of Si to be controlled by combinations of these
annealings.
Fiz. Tekh. Poluprovodn. 32, 1371–1377 (November 1998) 相似文献
9.
J. D. Benson L. O. Bubulac C. M. Lennon R. N. Jacobs P. J. Smith J. K. Markunas M. Jaime-Vasquez L. A. Almeida A. Stoltz J. A. Arias G. Brill Y. Chen P. S. Wijewarnasuriya M. F. Vilela J. Peterson S. M. Johnson D. D. Lofgreen D. Rhiger E. A. Patten J. Bangs 《Journal of Electronic Materials》2013,42(11):3217-3223
The crystalline structure and impurity profiles of HgCdTe/CdTe/alternate substrate (AS; Si and GaAs are possibilities) and CdTe/AS were analyzed by secondary-ion mass spectrometry, atomic force microscopy, etch pit density analysis, and scanning transmission electron microscopy. Impurities (Li, Na, and K) were shown to getter in as-grown CdTe/Si epilayers at in situ Te-stabilized thermal anneal (~500°C) interfaces. In HgCdTe/CdTe/Si epilayers, indium accumulation was observed at Te-stabilized thermal anneal interfaces. Impurity accumulation was measured at HgCdTe/CdTe and CdTe/ZnTe interfaces. Processing anneals were found to nearly eliminate the gettering effect at the in situ Te-stabilized thermal anneal interfaces. Impurities were found to redistribute to the front HgCdTe/CdTe/Si surface and p–n junction interfaces during annealing steps. We also investigated altering the in situ Te-stabilized thermal anneal process to enhance the gettering effect. 相似文献
10.
Rapid thermal annealing (RTA) technology offers potential advantages for GaAs MESFET device technology such as reducing dopant
diffusion and minimizing the redistribution of background impurities. LEC semi-insulating GaAs substrates were implanted with
Si at energies from 100 to 400 keV to doses from 1 × 1012 to 1 × 1014/cm2. The wafers were encapsulated with Si3N4 and then annealed at temperatures from 850-1000° C in a commercial RTA system. Wafers were also annealed using a conventional
furnace cycle at 850° C to provide a comparison with the RTA wafers. These implanted layers were evaluated using capacitance-voltage
and Hall effect measurements. In addition, FET’s were fabricated using selective implants that were annealed with either RTA
or furnace cycles. The effects of anneal temperature and anneal time were determined. For a dose of 4 × 1012/cm2 at 150 keV with anneal times of 5 seconds at 850, 900, 950 and 1000° C the activation steadily increased in the peak of the
implant with overlapping profiles in the tail of the profiles, showing that no significant diffusion occurs. In addition,
the same activation could be obtained by adjusting the anneal times. A plot of the equivalent anneal times versus 1/T gives
an activation energy of 2.3 eV. At a higher dose of 3 × 1013 an activation energy of 1.7 eV was obtained. For a dose of 4 × 1012 at 150 keV both the RTA and furnace annealing give similar activations with mobilities between 4700 and 5000 cm2/V-s. Mobilities decrease to 4000 at a dose of 1 × 1013 and to 2500 cm2/V-s at 1 × 1014/cm2. At doses above 1 × 1013 the RTA cycles gave better activation than furnace annealed wafers. The MESFET parameters for both RTA and furnace annealed
wafers were nearly identical. The average gain and noise figure at 8 GHz were 7.5 and 2.0, respectively, for packaged die
from either RTA or furnace annealed materials. 相似文献
11.
Surface roughening in ion implanted 4H-silicon carbide 总被引:1,自引:0,他引:1
M. A. Capano S. Ryu J. A. Cooper Jr. M. R. Melloch K. Rottner S. Karlsson N. Nordell A. Powell D. E. Walker Jr. 《Journal of Electronic Materials》1999,28(3):214-218
Silicon carbide (SiC) devices have the potential to yield new components with functional capabilities that far exceed components
based on silicon devices. Selective doping of SiC by ion implantation is an important fabrication technology that must be
completely understood if SiC devices are to achieve their potential. One major problem with ion implantation into SiC is the
surface roughening that results from annealing SiC at the high temperatures which are needed to activate implanted acceptor
ions, boron or aluminum. This paper examines the causes and possible solutions to surface roughening of implanted and annealed
4H-SiC. Samples consisting of n-type epilayers (5 × 1015 cm−3, 4 μm thick) on 4H-SiC substrates were implanted with B or Al to a total dose of 4 × 1014 cm−2 or 2 × 1015 cm−2, respectively. Roughness measurements were made using atomic force microscopy. From the variation of root mean square (rms)
roughness with annealing temperature, apparent activation energies for roughening following implantation with Al and B were
1.1 and 2.2 eV, respectively, when annealed in argon. Time-dependent activation and surface morphology analyses show a sublinear
dependence of implant activation on time; activation percentages after a 5 min anneal following boron implantation are about
a factor of two less than after a 40 min anneal. The rms surface roughness remained relatively constant with time for anneals
in argon at 1750°C. Roughness values at this temperature were approximately 8.0 nm. Annealing experiments performed in different
ambients demonstrated the benefits of using silane to maintain good surface morphology. Roughnesses were 1.0 nm (rms) when
boron or aluminum implants were annealed in silane at 1700°C, but were about 8 and 11 nm for B and Al, respectively, when
annealed in argon at the same temperature. 相似文献
12.
Mokhberi A. Griffin P.B. Plummer J.D. Paton E. McCoy S. Elliott K. 《Electron Devices, IEEE Transactions on》2002,49(7):1183-1191
Ultra-low energy implants were used in combination with rapid thermal anneals in the temperature range 900°C-1050°C to study dopant activation in silicon. First, relatively long time anneals were performed in a conventional tungsten-based RTA to investigate the activation mechanisms. The activation was monitored using Hall measurement, where the rate of electrical activation was considered by measuring the time it takes to reach 50% activation. Using Arrhenius fits, an activation energy was extracted, and it was found that while boron has a mean activation energy for electrical activation of 4.7 eV in agreement with previous studies, arsenic and phosphorus have thermal activation energies of 3.6 eV and 4.1 eV, respectively. The 4.7 eV activation energy for boron is believed to be related to a point defect driven mechanism for electrical activation. Electrical activation of arsenic and phosphorus, however, seems to be related to dopant diffusion. In the second set of experiments, an arc lamp system was utilized to perform ultra-sharp spike anneals. For both dopants, it was found that for a given temperature, there is an optimum ramp-rate that produces the desired dopant activation and junction depth 相似文献
13.
Doping profiles and electrical properties are investigated on SiC samples doped with single energy implants from nitrogen.
The profiles are analyzed using Pearson distributions for different implantation energies and temperatures. Implantations
are performed for temperatures up to 1200°C. Diffusion during high temperature implantation is investigated and the diffusion
coefficients measured range from 1.09 × 10−15 to 1.53 × 10−14cm2/s depending on temperature. The activation energy for implantation enhanced diffusion is estimated to be 0.91 eV. A comparison
is made with diffusion during annealing. The activated dopants from high temperature implantation are investigated by the
Hall probe method, showing that activation and mobility increase with temperature. 相似文献
14.
Rapid thermal diffusion of zinc into semi-insulating GaAs from spin-on Zn doped silica film was performed. Spin-on films act
both as Zn diffusion sources and GaAs surface encapsulant layer against decomposition during the rapid thermal diffusion.
The very shallowp
+ layers were obtained at a diffusion temperature of 900° C for 5 sec. Non-alloyed ohmic contacts to thesep
+ layers were achieved with an average contact resistivity of 2.4 × 10−6
Ω cm2. The interface is very smooth. The zinc diffusion coefficient for rapid thermal diffusion with effective diffusion time of
6 sec at 900° C was numerically calculated from SIMS profiles. In contrast to the common Longini-Weisberg-Blanc model, the
rapid thermal diffusion is under nonequilibrium condition. Complications due to interstitial-substitutional nonequilibrium,
vacancy supply resulted from the interface stress field, and zinc precipitation are briefly discussed. 相似文献
15.
MBE growth and characterization of in situ arsenic doped HgCdTe 总被引:2,自引:0,他引:2
A. C. Chen M. Zandian D. D. Edwall R. E. De Wames P. S. Wijewarnasuriya J. M. Arias S. Sivananthan M. Berding A. Sher 《Journal of Electronic Materials》1998,27(6):595-599
We report the results of in situ arsenic doping by molecular beam epitaxy using an elemental arsenic source. Single Hg1−xCdxTe layers of x ∼0.3 were grown at a lower growth temperature of 175°C to increase the arsenic incorporation into the layers.
Layers grown at 175°C have shown typical etch pit densities of 2E6 with achievable densities as low as 7E4cm−2. Void defect densities can routinely be achieved at levels below 1000 cm−2. Double crystal x-ray diffraction rocking curves exhibit typical full width at half-maximum values of 23 arcsec indicating
high structural quality. Arsenic incorporation into the HgCdTe layers was confirmed using secondary ion mass spectrometry.
Isothermal annealing of HgCdTe:As layers at temperatures of either 436 or 300°C results in activation of the arsenic at concentrations
ranging from 2E16 to 2E18 cm−3. Theoretical fits to variable temperature Hall measurements indicate that layers are not compensated, with near 100% activation
after isothermal anneals at 436 or 300°C. Arsenic activation energies and 77K minority carrier lifetime measurements are consistent
with published literature values. SIMS analyses of annealed arsenic doping profiles confirm a low arsenic diffusion coefficient. 相似文献
16.
Photocapacitance (PHCAP) measurements have been carried out on GaP crystals grown by the liquid-encapsulated Czochralski (LEC)
method with heat treatment under various phosphorus-vapor pressures at different temperatures. Electron traps of EC−1.1 eV, EC−1.6 eV, EC−1.9 eV, and a hole trap of EV+2.26 eV are mainly detected. The phosphorus-vapor pressure dependence of the EC−1.9 eV trap density and their diffusion behavior indicate that they are interstitial phosphorus atoms. The densities of both
EC−1.1 eV and EC−1.6 eV traps are strongly dependent on the shallow impurity concentrations. Moreover, the density of EC−1.1 eV traps increases with increasing phosphorus-vapor pressure. From these results, we suggest that EC−1.1 eV traps are the complexes of shallow donors and antisite phosphorus atoms. Deep-level densities in GaP crystals after
annealing at 860°C or 960°C for 60 min are decreased almost one order of magnitude lower than those in untreated substrate
crystals, which should have occurred via out-diffusion of interstitial phosphorus atoms. However, such an effect is not prominent
for 800°C treatment for 60 min. 相似文献
17.
M. A. Capano R. Santhakumar R. Venugopal M. R. Melloch J. A. Cooper Jr. 《Journal of Electronic Materials》2000,29(2):210-214
Sheet resistances in nitrogen- and phosphorus-implanted 4H-SiC are measured to assess the time and temperature dependencies of this variable. In 4H-SiC implanted with 3 × 1015 cm?2 nitrogen ions to a depth of 2800 Å, the minimum sheet resistance observed is 534 Ω/□. The minimum sheet resistance in 4H-SiC implanted with 4 × 1015 cm?2 phosphorus ions to a depth of 4000 Å is 51 Ω/□, a record low value for any implanted element into any polytype of SiC. Time-independent sheet resistances are observed following anneals at 1700°C for nitrogen and phosphorus samples. Lower temperature anneals produce sheet resistances which decrease monotonically with increasing time of anneal. Overall, sheet resistances from phosphorus-implanted 4H-SiC are an order of magnitude below those measured from nitrogen implanted samples. The response of phosphorus to low-temperature annealing is significant, and sheet resistances below 500 Ω/□ are achieved at 1200°C. Activation of phosphorus is attempted in an oxidizing atmosphere with and without prior argon annealing. A three-hour gate oxidation in wet O2 at 1150°C, followed by a 30 min argon anneal, produced a sheet resistance of 1081 Ω/□. Oxidation after argon annealing caused sheet resistances to increase by about 20% compared to samples subjected solely to argon annealing. It is also found that oxide growth rates are much higher over phosphorus implanted than over unimplanted 4H-SiC. Reasons for the disparity in sheet resistances between nitrogen and phosphorus implants, and for the difference in oxide growth rates are suggested. 相似文献
18.
Atomic profiles of ion-implanted Be and S in GaAs have been measured as a function of implant fluence and annealing temperature.
Concentration versus depth profiles were ob-tained by means of secondary ion mass spectrometry (SIMS) techniques. Pyrolytically
deposited and sputter-coated Si02 and Si3N4 films were used as encapsulants for the 500 to 900° annealing study. Semi-insulating GaAs was implanted with 200 keV34S+ to fluences of 1 × 1014 and 52× 1014/cm2, and 100 keV9Be+ in the 1 × 1013 to 1 × 1015/cm2 fluence range. The S profiles did not change significantly after annealing at 800°C, although there was some skewing after
annealing above 600°C. In contrast, the Be profiles showed significant changes and a decrease in the peak concentration for
the ≥ 5 × 10T4/cm2 implants after a 700°C anneal. After a 800°C anneal the Be profile was essentially flat with a monotonic decrease from the
surface into the implanted re-gion and a 900°C anneal caused a further decrease in the Be concentration. Profiles of Be implants
of ≤ 1 × 1014/cm2 did not change significantly after annealing indicating that the higher fluence cases were related to solubility effects.
This work supported by the Naval Electronic Systems Command and the Office of Naval Research. 相似文献
19.
A. J. Steckl J. Devkajan W. J. Choyke R. P. Devaty M. Yoganathan S. W. Novak 《Journal of Electronic Materials》1996,25(5):869-873
The effect of post-implantation anneal on erbium-doped 6H-SiC has been investigated. 6H-SiC has been implanted with 330 keV
Er+ at a dose of 1 × 1013 /cm2. Er depth profiles were obtained by secondary ion mass spectrometry (SIMS). The as-implanted Er-profile
had a peak concentration of∼1.3 × 1018/cm3 at a depth of 770Å. The samples were annealed in Ar at temperatures from 1200 to 1900°C. The photoluminescence intensity
integrated over the 1.5 to 1.6 μm region is essentially independent of annealing temperature from 1400 to 1900°C. Reduced,
but still significant PL intensity, was measured from the sample annealed at 1200°C. The approximate diffusivity of Er in
6H SiC was calculated from the SIMS profiles, yielding values from 4.5 × 10−16 cm2/s at 1200°C to 5.5 × 10−15 cm2/s at 1900°C. 相似文献
20.
E. D. Jones J. Malzbender N. Shaw P. Capper J. B. Mullin 《Journal of Electronic Materials》1995,24(9):1225-1229
Studies on the diffusion of iodine into CdTe, mercury cadmium telluride (Hg0.8Cd0.2Te, referred to as MCT) and zinc cadmium telluride (Zn0.5Cd0.95Te, referred to as ZCT) in the temperature range of 20 to 600°C are compared and discussed. The concentration profiles were
measured using a radiotracer sectioning technique. As with the diffusion studies using the halogens into CdTe, the profiles
were composed of four parts to which a computer package consisting of the sum of four complementary error functions (erfc)
gave satisfactory fits. The diffusivity for the diffusion of iodine into MCT was faster than for the diffusion into CdTe,
which was faster than for the diffusion into ZCT. The high diffusivity for the fastest profile part at 20°C indicates that
when iodine is diffused from the vapor into these materials, it is not a suitable long term stable dopant in devices where
sharp junctions are required. 相似文献