Anomalous Diffusion of Intrinsic Defects in K+ Implanted ZnO using Li as Tracer

2012 ◽  
Vol 1394 ◽  
Author(s):  
L. Vines ◽  
P.T. Neuvonen ◽  
A. Yu. Kuznetsov ◽  
J. Wong-Leung ◽  
C. Jagadish ◽  
...  

ABSTRACTPotassium (K) ions have been implanted in hydrothermally grown ZnO to a dose of 1 × 1015 cm-2, followed by isochronal annealing in a tube furnace (30min) and by rapid thermal annealing (30s) on two separate samples. For annealing temperatures below 700°C, only a minor redistribution of Li is observed behind the projected range of the K+ ions. At temperatures between 700 and 750°C, however, both annealing treatments show a wide region behind the implantation peak which is depleted of Li, and this depletion is used as a tracer to monitor diffusion of intrinsic defects like the Zn interstitial. The results are interpreted as Zn interstitials being released from the implanted region in a burst at temperatures above ∼700°C, followed by rapid migration, replacement of Li on Zn site through the kick-out mechanism, and migration of Li away from the active region.

1991 ◽  
Vol 240 ◽  
Author(s):  
T. E. Kazior ◽  
S. K. Brierley

ABSTRACTMBE grown GaAs/Al0.25Ga0.75As/In0.85Ga0.85 As structures were subjected to SiNx capped rapid thermal annealing and their electrical and material properties were characterized by Hall measurements and photoluminescence (PL). Low temperature (5°K) PL spectra from undoped structures annealed up to 900°C indicated negligible intermixing at the AIGaAs/lnGaAs interface. For planar doped structures (Nd≈5×1012/cm2) the Hall mobility began to decrease at anneal temperatures as low as 800°C with significant degradation observed for annealing temperatures at 850°C. This data is supported by PL spectra which indicate no significant change for samples annealed at 800°C. For the samples annealed at ≥ 850°C a large increase in the full width at half maximum of the transitions from the electron sub-bands of the InGaAs quantum well were observed, suggesting that the change in electrical characteristics is primarily due to diffusion of the Si doping pulse. In contrast. Hall measurement of uniformly doped structures reveal only small decreases in mobility and no significant change in sheet concentration for anneal temperatures up to 900°C and doping levels up to 2.5×1018/cm3. PL spectra reveal no structural changes.


1989 ◽  
Vol 146 ◽  
Author(s):  
Y. M. Kim ◽  
G. Q. Lo ◽  
D. L. Kwong ◽  
H. H. Tseng ◽  
R. Hance

ABSTRACTEffects of defect evolution during rapid thermal annealing (RTA) on the anomalous diffusion of ion implanted boron have been studied by implanting silicon ions prior to boron implantation with doses ranging from 1 × 1014cm−2 to 1 × 1016cm−2 at energies ranging from 20 to 150 KeV into silicon wafers. Diffusion of boron atoms implanted into a Si preamorphized layer during RTA is found to be anomalous in nature, and the magnitude of boron displacement depends on the RTA temperature. While RTA of preamorphized samples at 1150°C shows an enhanced boron displacement compared to that in crystalline samples, a reduced displacement is observed in preamorphized samples annealed by RTA at 1000°C. In addition, low dose pre-silicon implantation enhances the anomalous displacement significantly, especially at high RTA temperatures (1 150°C). Finally, the anomalous diffusion is found to depend strongly on the defect evolution during RTA.


1992 ◽  
Vol 268 ◽  
Author(s):  
Ikasko C. Dehm ◽  
H. Ryssel

ABSTRACTIn this study, the critical dose for ion-beam mixing of Co and Si with Ge-ions which results in homogenous CoSi2 formation after rapid thermal annealing was found. For this purpose, Co was deposited by sputtering on chemically cleaned, <100>-oriented Si and subsequently mixed with Ge ions at doses in the range of 2. 1014 to 1. 1015 cm−2. Silicidation was performed in a rapid thermal annealing (RTA) system at temperatures between 700° and 100°C. Rutherford backscattering measurements showed that annealing at 700°C results in an incomplete reaction when ion-beam mixing at a dose of 2.1014 cm−2 or no ion-beam mixing was performed. After annealing at 1000°C, TEM samples revealed an inhomogeneous CoSi2 film consisting of large grains embedded in the Si. Mixing at doses at or above 5.1014 cm−2 and subsequent RTA at 700°C resulted in uniform CoSi2 layers. Higher annealing temperatures cause larger grains and resistivity values as low as 18 μΩcm. Therefore, we demonstrated that the critical dose leading to complete formation of smooth CoSi2 films with abrupt interface is 5.1014 cm−2 which is nearly the same value as the amorphization dose of Ge in Si.


1988 ◽  
Vol 144 ◽  
Author(s):  
B.J. Skromme ◽  
N.G. Stoffel ◽  
A.S. Gozdz ◽  
M.C. Tamargo ◽  
S.M. Shibli

ABSTRACTWe describe the effects of rapid thermal annealing on the photoluminescence (PL) and electrical properties of heteroepitaxial ZnSe grown by molecular beam epitaxy on GaAs, using either no cap or plasma-deposited SiO2, Si3N4, or diamond-like C caps, and annealing temperatures from 500 to 800°C. Capless anneals (in contact with GaAs) produce badly degraded PL properties, while capped anneals can prevent this degradation. We show that Si3N4 is significantly more effective in preventing Zn out-diffusion through t e cap than previously employed SiO2 films, as evidenced by less pronounced PL features related to the creation of Zn vacancies during the anneal. Implant damage tends to enhance the Zn vacancy formation. Rapid thermal annealing with Si3N4 caps is shown to optically activate shallow N acceptor implants.


1987 ◽  
Vol 104 ◽  
Author(s):  
G. Langouche ◽  
D. Schroyen ◽  
H. Bemelmans ◽  
M. Van Rossum ◽  
W. Deraedt ◽  
...  

ABSTRACTTe atoms were implanted in GaAs with doses ranging from 1013 to 1016 atoms/cm2, and annealed with the rapid thermal annealing technique. The samples were studied by Mössbauer Spectroscopy, Rutherford Backscattering Spectroscopy – Channeling, and the Van der Pauw-method. While at the lowest implantation dose an unperturbed substitutional site is observed at all annealing temperatures, at the highest implantation dose a strong deviation from a central position in an unperturbed configuration is observed at all temperatures. At the intermediate doses a high degree of substitutionality is observed between annealing temperatures of 200°C and 500°C only.


2005 ◽  
Vol 865 ◽  
Author(s):  
Xuege Wang ◽  
Sheng. S. Li ◽  
V. Craciun ◽  
S. Yoon ◽  
J. M. Howard ◽  
...  

AbstractRapid thermal annealing (RTA), with fast ramp up and down rates, was performed on several Cu(In,Ga)Se2 (CIGS) films and solar cells under various peak annealing temperatures and holding times. The XRD, SEM, Hall- effect, photo J-V, and quantum efficiency (Q-E) measurements were made on CIGS films and cells before and after RTA treatments to study the effects of RTA on the CIGS film properties and cell performance. The results show that RTA treatments under optimal annealing condition can provide significant improvements in the electrical properties (resistivity, carrier concentration, and mobility) of CIGS films and cell performance while preserving the film composition and microstructure morphology.


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)


1985 ◽  
Vol 52 ◽  
Author(s):  
S. J. Pennycook ◽  
R. J. Culbertson

ABSTRACTDuring the rapid thermal annealing of ion implanted layers, trapped interstitials are responsible for transient enhanced dopant diffusion and the formation of a band of defects at the mean projected ion range. We describe the detailed nature and extent of these effects and show how they can be predicted in practice. We present a model which explains why trapping only occurs with group V implantation and describe double implantation experiments which confirm the model and show how the formation of projected range defects can be suppressed.


1991 ◽  
Vol 138 (4) ◽  
pp. 1122-1130 ◽  
Author(s):  
Y. M. Kim ◽  
G. Q. Lo ◽  
H. Kinoshita ◽  
D. L. Kwong ◽  
H. H. Tseng ◽  
...  

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