Rapid Thermal Annealing of Ion-Implanted Silicon and Gallium Arsenide

1983 ◽  
Vol 23 ◽  
Author(s):  
J. Narayan

ABSTRACTWe have investigated the annealing of ion implantation damage (in the form of amorphous layers and/or the layers containing only dislocation loops) in silicon and gallium arsenide. The annealing of amorphous layers occurs by solid-phase-epitaxial growth and that of dislocation loops involves primarily loop-coalescence as a result of conservative climb and glide processes. The annealing of disolated loops occurs primarily by a bulk diffusion process. Almost a “complete” annealing of displacement damage is possible for shallow implants provided loop–coalescence does not lead to the formation of cross–grid of dislocations. For deep implants, the free surface cannot provide an effective sink for defects as in the case of shallow implants. Dopant profiles can be controlled to less than 1000 Å in layers having good electrical properties. The enhanced diffusion of dopants is observed probably due to entrapment of point defects in the annealed regions.

1982 ◽  
Vol 13 ◽  
Author(s):  
J.S. Williams

ABSTRACTThis paper provides a brief overview of the application of transient annealing to the removal of ion implantation damage and dopant activation in GaAs. It is shown that both the liquid phase and solid phase annealing processes are more complex in GaAs than those observed in Si. Particular attention is given to observations of damage removal, surface dissociation, dopant redistribution, solubility and the electrical properties of GaAs. The various annealing mechanisms are discussed and areas in need of further investigation are identified.


1992 ◽  
Vol 262 ◽  
Author(s):  
J.W. Honeycutt ◽  
J. Ravi ◽  
G. A. Rozgonyi

ABSTRACTThe effects of Ti and Co silicidation on P+ ion implantation damage in Si have been investigated. After silicidation of unannealed 40 keV, 2×1015 cm-2 P+ implanted junctions by rapid thermal annealing at 900°C for 10–300 seconds, secondary ion mass spectrometry depth profiles of phosphorus in suicided and non-silicided junctions were compared. While non-silicided and TiSi2 suicided junctions exhibited equal amounts of transient enhanced diffusion behavior, the junction depths under COSi2 were significantly shallower. End-of-range interstitial dislocation loops in the same suicided and non-silicided junctions were studied by planview transmission electron microscopy. The loops were found to be stable after 900°C, 5 minute annealing in non-silicided material, and their formation was only slightly effected by TiSi2 or COSi2 silicidation. However, enhanced dissolution of the loops was observed under both TiSi2 and COSi2, with essentially complete removal of the defects under COSi2 after 5 minutes at 900°C. The observed diffusion and defect behavior strongly suggest that implantation damage induced excess interstitial concentrations are significantly reduced by the formation and presence of COSi2, and to a lesser extent by TiSi2. The observed time-dependent defect removal under the suicide films suggests that vacancy injection and/or interstitial absorption by the suicide film continues long after the suicide chemical reaction is complete.


1997 ◽  
Vol 469 ◽  
Author(s):  
H. S. Chao ◽  
P. B. Griffin ◽  
J. D. Plummer

ABSTRACTThe transient enhanced diffusion behavior of B after ion implantation above the amorphization threshold is investigated. The experimental structure uses a layer of epitaxially grown Si, uniformly doped with B to act as a diffusion monitor. Wafers using this structure are implanted with amorphizing doses of Si, As, or P and annealed for various times at various temperatures. The experimental results show that upon annealing after Si implantation, there is a large amount of B pile-up that occurs at the amorphous/crystalline (A/C) interface while B is depleted from the region just beyond the A/C interface. This pile-up/depletion phenomenon can be attributed to the dislocation loops that form at the A/C interface. These loops act as sinks for interstitial point defects. There is also B pile-up/depletion behavior for As and P implants as well. However, this behavior may be explained by an electric field enhancement effect. While dislocation loops are known to form at the A/C interface for all of the investigated implant conditions, it appears that while they are necessary to simulate for Si amorphizing implants, they may not be necessary to simulate for As and P amorphizing implants.


1987 ◽  
Vol 104 ◽  
Author(s):  
S. D. Brotherton ◽  
J. R. Ayres ◽  
J. B. Clegg ◽  
B. J. Goldsmith

ABSTRACTAn examination of Si+ pre-amorphised p+n structures as a function of Si+ implantation energy and solid phase epitaxial regrowth temperature has revealed three different classes of defect all of which may influence the characteristics of the junction. They are point defects responsible for high concentrations of deep level donors, and interstitial dislocation loops both causing leakage current degradation, and excess silicon interstitials leading to enhanced junction movement.


1984 ◽  
Vol 36 ◽  
Author(s):  
S. J. Pennycook ◽  
J. Narayan ◽  
R. J. Culbertson

ABSTRACTWe have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. We show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase-epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. We discuss the conditions under which the various effects may or may not be observed, and discuss preliminary observations on As+ implanted Si.


1995 ◽  
Vol 396 ◽  
Author(s):  
M. Kase ◽  
H. Mori

AbstractFor low energy B (LEB) implantation into Si, the channeling tail is larger than for BF2+ implantation, so Ge+ preamorphization is expected to provide a shallower junction. We studied the Ge+ and B+ implantation damages and the damage-induced B diffusion. The substrate implanted Ge+ with 2×l014 cm-2, that is, a complete amorphization, retains less residual defects after RTA. However the sheet resistivity (S) is higher than the sample implanted with only LEB. Solid phase epitaxy (SPE) of amorphized layer causes B out-diffusion. The diffusion length of the amorphized substrate is smaller than that of LEB. We expect that the B diffusion is enhanced by the LEB damage, which corresponds to the enhanced diffusion of light damage.


1983 ◽  
Vol 13 ◽  
Author(s):  
J. Narayan ◽  
R. T. Young

ABSTRACTWe have investigated flame annealing of ion implantation damage (consisting of amorphous layers and dislocation loops) in (100) and (111) silicon substrates. The temperature of a hydrogen flame was varied from 1050 to 1200°C and the interaction time from 5 to 10 seconds. Detailed TEM results showed that a “defect-free” annealing of amorphous layers by solid-phase-epitaxial growth could be achieved up to a certain concentration. However, dislocation loops in the region below the amorphous layer exhibited coarsening,i.e., the average loop size increased while the number density of loops decreased. Above a critical loop density, which was found to be a function of ion implantation variables and substrate temperature, formations of 90° dislocations (a cross-grid of dislocation in (100) and a triangular grid in (111) specimens) were observed. Electrical (Van der Pauw) measurements indicated nearly a complete electrical activation of dopants with mobility comparable to pulsed laser annealed specimens. The characteristics of p-n junction diodes showed a good diode perfection factor of 1.20–1.25 and low reverse bias currents.


Author(s):  
T. Sands

Further advances in the miniaturization and integration of GaAs-based electronic and photonic devices necessitate the development of low-resistance (ohmic) and rectifying (Schottky) contacts that are thermally stable and morphologically uniform. In principle, optimum stability and morphology can be achieved by codepositing intermetallic phases (e.g. NiGa, CoGa and AuGa2) that are known to be in thermodynamic equilibrium with GaAs at the relevant temperatures. Such an approach must, however, be combined with a mechanism by which the GaAs may be doped or alloyed to yield contacts with a range of electrical properties (e.g. low-barrier ohmic, tunneling ohmic or high-barrier Schottky contacts). In this paper, the fabrication of stable and uniform ohmic and Schottky contacts using limited reactions between GaAs and intermetallic phases that contain the doping (e.g. Ge or Si) or alloying (e.g. Al or In) element is described. The fact that these reactions are limited - involving only 5-10 nm of GaAs at the metallization/GaAs interface - makes TEM an essential tool for characterizing these contacts.


1991 ◽  
Vol 238 ◽  
Author(s):  
H. L. Meng ◽  
K. S. Jones ◽  
S. Prussin

ABSTRACTIon implantation and thermal oxidation are device fabrication processes that lead to perturbation of equilibrium point defects concentration in silicon. This study investigates the interaction between oxidation-induced point defects and type II dislocation loops intentionally introduced in silicon via ion implantation. The type II dislocation loops were introduced via Si implants into (100) Si wafers at 50 keV to a dose ranging from 2×1015 to 1×1016/cm2. The subsequent furnace annealing at 900 °C was done for times between 30 min and 4 hr in either a dry oxygen or nitrogen ambient. Plan-view transmission electron microscopy (PTEM) was used to characterize the increase in atom concentration bound by dislocation loops as a result of oxidation. The results show type II dislocation loops can be used as point defect detector and they are efficient in measuring oxidation-induced point defects. It is also shown that the measured net interstitials flux trapped by dislocation loops is linearly proportional to the total supersaturation of interstitials as measured by oxidation enhanced diffusion (OED) studies.


Author(s):  
Byung-Teak Lee

Grown-in dislocations in GaAs have been a major obstacle in utilizing this material for the potential electronic devices. Although it has been proposed in many reports that supersaturation of point defects can generate dislocation loops in growing crystals and can be a main formation mechanism of grown-in dislocations, there are very few reports on either the observation or the structural analysis of the stoichiometry-generated loops. In this work, dislocation loops in an arsenic-rich GaAs crystal have been studied by transmission electron microscopy.The single crystal with high arsenic concentration was grown using the Horizontal Bridgman method. The arsenic source temperature during the crystal growth was about 630°C whereas 617±1°C is normally believed to be optimum one to grow a stoichiometric compound. Samples with various orientations were prepared either by chemical thinning or ion milling and examined in both a JEOL JEM 200CX and a Siemens Elmiskop 102.


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