Stress-Related Defects in Implanted Locos + Trench - Isolated Structures

1992 ◽  
Vol 262 ◽  
Author(s):  
Barbara Vasquez ◽  
N. David Theodore
Keyword(s):  
Stress Fields ◽  
High Dose ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Defect Engineering ◽  
Local Oxidation ◽  
Trench Isolation ◽  
And Behavior ◽  
Dislocation Sources ◽  
Reducing Stress

ABSTRACTPoly-buffered local-oxidation of silicon + trench-isolation (PBLT) is a technique being explored for device isolation. In an earlier study, we had reported the presence of dislocations associated with a combination of high-dose (∼5E14 cm2) phosphorous implants and PBLT isolation. In the present study, the behavior of extended defects present in the structures is analyzed in greater detail. The origin and behavior of the defects is modelled to explore potential mechanisms to explain the observations. Implantation induced dislocation-loops interact with stress fields associated with PBLT isolation-trenches. Some of the implant loops (in the presence of a stress field) transform to dislocation sources which then create glide dislocations in the structures. Strategies for defect engineering are discussed, including reducing implant-induced damage (lowering the implant dose) or reducing stress fields (by moving the edge of the implanted region away from the trench). Defect densities can be reduced or eliminated.

Defect-Characterization in Implanted Locos + Trench-Isolated Structures

1991 ◽  
Vol 239 ◽  
Author(s):  
N. David Theodore ◽  
Barbara Vasquez ◽  
Peter Fejes
Keyword(s):  
Integrated Circuits ◽  
Cross Section ◽  
High Dose ◽  
Defect Characterization ◽  
Dislocation Loops ◽  
Etch Pits ◽  
Local Oxidation ◽  
Silicon Integrated Circuits ◽  
Trench Isolation ◽  
Dislocation Sources

ABSTRACTAs device dimensions decrease in silicon integrated-circuits, conventional LOCOS (local-oxidation of silicon) isolation becomes inadequate to meet dimensional demands. Variations on LOCOS are therefore being explored for further miniaturization of devices. One such variation involves poly-buffered LOCOS + trench-isolation (PBLT). In this study, PBLT structures were characterized using TEM. Wright-etched cross-section SEM micrographs showed etch-pits associated with a combination of high-dose (> 5E14 cm-2) phosphorous implants and PBLT isolation. TEM characterization showed that dislocations were formed in the structures for a combination of high-dose (1E15 cm-2) phosphorous implants (followed by an anneal) and PBLT isolation. Structures exposed to lower-dose (1E14 cm-2) implants showed no defects and neither did 1E15 implanted structures prior to annealing. The results are modelled in terms of the stress configurations present in the structures, and in terms of dislocation-sources resulting from implantation-related dislocation-loops. The dislocation-sources operate in the presence of stresses associated with the isolation-trenches. Glide-loops form, which then grow in response to stresses in the structures and dislocations result on glide planes.

Behavior of Damage in Selectively Implanted SiGe/Si

1993 ◽  
Vol 319 ◽  
Author(s):  
N. David Theodore ◽  
Gordon Tam ◽  
Jim Whitfield ◽  
Jim Christiansen ◽  
John Steele
Keyword(s):  
Heterojunction Bipolar Transistors ◽  
High Speed ◽  
Critical Thickness ◽  
Bipolar Transistors ◽  
Electrical Performance ◽  
Misfit Dislocations ◽  
Extended Defects ◽  
Dislocation Loops ◽  
And Behavior ◽  
Dislocation Sources

AbstractEpitaxial SiGe/Si layers are being extensively investigated for use in base regions of high-speed heterojunction bipolar-transistors (HBTs). Extended defects can be formed in SiGe/Si layers by ion-implantation. Defects, once formed in the layers, can negatively impact electrical performance and also future reliability of the HBTs. The present study investigates the interaction between selective-implant damage and strained SiGe/Si layers of sub-critical thickness. Implant-damage is observed to form dislocation-sources at the edges of implanted regions in SiGe/Si heterolayers. The dislocation sources produce glide dislocation loops. Segments of these loops glide down to SiGe/Si interfaces causing misfit dislocations to arise at interfaces in the heterolayers. Misfitdislocations are formed in directions parallel to and perpendicular to the <110> edge of the implanted region. Dislocations propagate out to a distance of ∼100-150 nm past the edge of the implant in the case of Si0.9Ge0.1/Si layers of sub-critical thickness. The origin and behavior of these defects is discussed.

Formation of defects in implanted hipox-structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1406-1407
Author(s):  
Peter Pegler ◽  
N. David Theodore ◽  
Ming Pan
Keyword(s):  
High Pressure ◽  
Cross Section ◽  
Semiconductor Devices ◽  
Silicon Substrates ◽  
Processing Conditions ◽  
Pressure Oxidation ◽  
Deep Trench ◽  
Local Oxidation ◽  
Trench Isolation ◽  
And Behavior

High-pressure oxidation of silicon (HIPOX) is one of various techniques used for electrical-isolation of semiconductor-devices on silicon substrates. Other techniques have included local-oxidation of silicon (LOCOS), poly-buffered LOCOS, deep-trench isolation and separation of silicon by implanted oxygen (SIMOX). Reliable use of HIPOX for device-isolation requires an understanding of the behavior of the materials and structures being used and their interactions under different processing conditions. The effect of HIPOX-related stresses in the structures is of interest because structuraldefects, if formed, could electrically degrade devices.This investigation was performed to study the origin and behavior of defects in recessed HIPOX (RHIPOX) structures. The structures were exposed to a boron implant. Samples consisted of (i) RHlPOX'ed strip exposed to a boron implant, (ii) recessed strip prior to HIPOX, but exposed to a boron implant, (iii) test-pad prior to HIPOX, (iv) HIPOX'ed region away from R-HIPOX edge. Cross-section TEM specimens were prepared in the <110> substrate-geometry.

On the Energetics of Extrinsic Defects in Si and their Role in Nonequilibrium Dopant Diffusion

2000 ◽  
Vol 610 ◽  
Author(s):  
Alain Claverie ◽  
Filadelfo Cristiano ◽  
Benjamin Colombeau ◽  
Nicholas Cowern
Keyword(s):  
Formation Energy ◽  
Ostwald Ripening ◽  
High Dose ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Dynamical Equilibrium ◽  
Defect Interactions ◽  
Small Clusters ◽  
Dose Levels ◽  
Extrinsic Defects

AbstractIn this paper, we discuss the mechanisms by which small clusters evolve through “magic” sizes into {113} defects and then, at sufficiently high dose levels, transform into dislocation loops of two types. This ripening process is mediated by the interchange of free Si(int)s between different extended defects, leading to a decrease of their formation energy. The calculation of the supersaturation of free Si-interstitials in dynamical equilibrium with these defects shows a hierarchy of levels of nonequilibrium diffusion, ranging from supersaturations S of about 106 in the presence of small clusters, through 103 in the presence of {113} defects, to S in the range 100 down to 1 as loops are formed, evolve and finally evaporate. A detailed analysis of defect energetics has been carried out and it is shown that Ostwald ripening is the key concept for understanding and modelling defect interactions during TED of dopants in silicon.

Formation of defects in boron-implanted PEPBLT structures

1992 ◽  
Vol 50 (2) ◽  
pp. 1408-1409
Author(s):  
N. David Theodore ◽  
Sam Sundaram ◽  
Peter Fejes
Keyword(s):  
High Performance ◽  
Active Regions ◽  
Bipolar Transistors ◽  
High Dose ◽  
Extended Defects ◽  
Active Device ◽  
Device Scaling ◽  
Local Oxidation ◽  
C 30 ◽  
Field Oxide

Variations on LOCOS (local-oxidation of silicon) are being explored for device-isolation, to implement further miniaturization of VLSI devices. One such variation involves poly-encapsulated poly-buffered LOCOS + trench-isolation (PEPBLT). The method provides a means to support device scaling and to create self-aligned shallow field-oxide elements with minimal encroachment into active regions. In an earlier study, dislocations were observed to be associated with a combination of high-dose ∼1E15 cm−2 phosphorus implants and PEPBLT isolation. The present study investigates the effect of boron implants on similar PEPBLT structures. The effect of fabrication-related stresses in the structures is of interest because extended-defects, if formed, could electrically degrade transistors.PEPBLT structures were exposed to varied processing conditions to build high-performance bipolar transistors. Isolated active-device regions from the above structures were characterized using TEM. Some of the active regions were (i) implanted with 80 keV-8.5E15 cm−2 boron with no anneal, (ii) implanted with 80 keV- 8.5E15 cm−2 boron and annealed at 900°C/90’/N2 plus 1050°C/30” RTA during the course of processing, (iii) not implanted.

Microstructural characterization of implanted LOCOS + trench-isolated structures

1991 ◽  
Vol 49 ◽  
pp. 888-889
Author(s):  
N. David Theodore ◽  
Barbara Vasquez ◽  
Peter Fejes
Keyword(s):  
Active Regions ◽  
Microstructural Characterization ◽  
Extended Defects ◽  
Active Device ◽  
Deep Trench ◽  
Device Scaling ◽  
Local Oxidation ◽  
Trench Isolation ◽  
Field Oxide

As device dimensions decrease and circuit densities increase, conventional LOCOS (Local-Oxidation of Silicon) isolation presents a limitation due to lateral encroachment of the isolation-oxide. Variations in LOCOS, including poly-buffered LOCOS have been of interest as means to limit lateral encroachment of the field-oxide into the active device-region. Deep-trench isolation provides a means to support device scaling and in this work is integrated with poly-buffered LOCOS to create self-aligned shallow fieldoxide elements with minimal encroachment into active regions. Use of these technologies however requires an understanding of the behavior of the materials and structures being used and their interactions under different processing conditions. The effect of fabrication-related stresses in the structures is of interest because extended-defects, if formed, could electrically degrade devices.

Device Parametric Shift Mechanism Caused by Boron Halo Redistribution Resulting from Dose Rate Dependence of SDE Implant

2005 ◽  
Vol 864 ◽  
Author(s):  
Ukyo Jeong ◽  
Jinning Liu ◽  
Baonian Guo ◽  
Kyuha Shim ◽  
Sandeep Mehta
Keyword(s):  
Surface Region ◽  
Amorphous Region ◽  
Amorphous Layer ◽  
High Dose ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Near Surface ◽  
Enhanced Diffusion ◽  
Dose Rates ◽  
Pile Up

AbstractChange in dopant diffusion was observed for Arsenic source drain extension (SDE) implants when they were performed at various dose rates. The high dose SDE implant amorphizes the surface of the silicon substrate and the thickness of the amorphous layer is strongly influenced by the rate of dopant bombardment. It is well known that the ion implantation process introduces excess interstitials. While the amorphous region is completely re-grown into single crystal during subsequent anneal without leaving behind extended defects, interstitials that are injected beyond the amorphous layer lead to formation of {311} defects or dislocation loops in the end of range region. During thermal processing, these extended defects dissolve, release interstitials, which in turn lead to transient enhanced diffusion of underlying Boron halo dopant. Dopant depth profiles measured by SIMS revealed different amount of Boron pile-up in the near surface region, corresponding to different SDE implant dose rates. In CMOS devices, this surface pile-up would correlate with a Boron pile-up in the channel region that would lead to a shift in transistor characteristics. Through this investigation, we were able to explain the mechanism causing device characteristics shift resulted from SDE implant with the same dose and energy but different dose rates.

Geometry-dependence of defects in PBLT serpentines

1992 ◽  
Vol 50 (2) ◽  
pp. 1410-1411
Author(s):  
Peter Fejes ◽  
N. David Theodore ◽  
Han-Bin Liang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Active Regions ◽  
High Dose ◽  
Extended Defects ◽  
Transmission Electron ◽  
Geometry Dependence ◽  
Trench Isolation ◽  
Semiconductor Substrates ◽  
Field Oxide

Poly-buffered LOCOS + trench-isolation is a technique being explored for device-isolation on semiconductor substrates. The method creates self-aligned shallow field-oxide elements with minimal encroachment into active regions. In an earlier study/dislocations were observed in PBLT structures, associated with a combination of high-dose [∼1E15 cm−2] phosphorus implants and PBLT isolation. The present study investigates the effect of implant- and isolation-geometries on the formation of extended-defects in PBLT structures. The effect of fabrication-related stresses in the structures is of interest because extended-defects, once formed, can electrically degrade devices.PBLT structures were fabricated using varied implant- and isolation- geometries. Selected regions of the structures were exposed to 1E15 cm−2 phosphorus implants. Transmission electron microscopy was then used to characterize these regions. Some of the structures investigated were (i) trench with no adjacent implant, (ii) trench with an adjacent trench, but no implant, (iii) trench with a 1E15 cm−2 phosphorus implant placed ∼4 μm from the trench, (iv) trench with a 1E15 cm−2 phosphorus implant placed ∼2 μm from the trench, (v) doubly-kinked trench with a 1E15cm−2 phosphorus implant placed between the kinks.

Point Defect Engineering Applied to Shallow Junction ULSI Processing

1989 ◽  
Vol 147 ◽  
Author(s):  
George A. Rozgonyi ◽  
J. W. Honeycutt
Keyword(s):  
Point Defect ◽  
Extended Defects ◽  
Dislocation Loops ◽  
Defect Engineering ◽  
Process Technology ◽  
Plan View ◽  
Dopant Activation ◽  
Qualitative Understanding ◽  
Junction Formation ◽  
Induced Defects

AbstractWe describe how a simple qualitative understanding of the interfacial reactions occurring during typical ULSI processes for junction formation, dopant activation, and contact silicidation can be used to eliminate end-of-range interstitial dislocation loops and beneficially impact the diffusion of dopants. Following a brief discussion of the well-documented effects of oxidation and nitridation on extended defects and dopant diffusion, conditions for elimination of implantation-induced defects are specified. Cross-section and plan-view TEM along with angle lapping and chemical etching of implanted and diffused junctions are presented to illustrate the application of point defect engineering to process technology.

Highlights in the history of X-ray topography1

1995 ◽  
Vol 210 (6) ◽  
Author(s):  
A. R. Lang
Keyword(s):  
Magnetic Domain ◽  
Diffraction Theory ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Domain Structures ◽  
Structure Factors ◽  
History Of ◽  
Dislocation Sources ◽  
Non Destructive

AbstractX-ray topography provides a non-destructive method of mapping point-by-point variations in orientation and reflecting power within crystals. The discovery, made by several workers independently, that in nearly perfect crystals it was possible to detect individual dislocations by X-ray diffraction contrast started an epoch of rapid exploitation of X-ray topography as a new, general method for assessing crystal perfection. Another discovery, that of X-ray Pendellösung, led to important theoretical developments in X-ray diffraction theory and to a new and precise method for measuring structure factors on an absolute scale. Other highlights picked out for mention are studies of Frank-Read dislocation sources, the discovery of long dislocation helices and lines of coaxial dislocation loops in aluminium, of internal magnetic domain structures in Fe-3 wt.% Si, and of stacking faults in silicon and natural diamonds.

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