Precipitate and Defect Formation in Oxygen Implanted Silicon-on-Insulator Material

1987 ◽  
Vol 107 ◽  
Author(s):  
S.J. Krause ◽  
C.O. Jung ◽  
T.S. Ravi ◽  
S.R. Wilson ◽  
D.E. Burke
Keyword(s):  
Defect Formation ◽  
High Resolution Electron Microscopy ◽  
Superficial Layer ◽  
Silicon On Insulator ◽  
Precipitate Size ◽  
High Dose ◽  
High Heating Rate ◽  
Threading Dislocations ◽  
Resolution Electron ◽  
Annealing Cycle

AbstractThe formation and structure of defects and precipitates in high-dose oxygen implanted silicon-on-insulator material was directly studied by weak beam and high resolution electron microscopy. In as-implanted material, the edge of the oxygen implant profile contained 1.5 nm diameter precipitates at a density of 1019 cm2. Defects, including micrctwins, stacking faults, and (311) defects, were present in as-implanted material but no threading or loop dislocations were observed. This suggests that threading dislocations are formed in the thermal ramping and annealing cycle. In material annealed for different times and temperatures precipitate size was much more dependent on peak temperature rather than time-at-temperature indicating that oxygen diffusion distance is less important than thermodynamic factors in controlling precipitate size. Annealing from 1150°C to 1250°C produced threading dislocations and possible dislocation dipoles which extended through the superficial layer. Transient annealing of very low dose oxygen implanted Si produced loop and threading dislocations. This suggests that a high heating rate during precipitation will generate excess Si interstitials at a rate high enough to create high stresses at precipitates and form dislocations. A qualitative model for dislocation formation is proposed and processing conditions for reducing dislocation density are suggested.

Defect formation in oxygen-multiply implanted silicon-on-insulator material

1995 ◽  
Vol 53 ◽  
pp. 448-449
Author(s):  
J.C. Park ◽  
J.D. Lee ◽  
S.J. Krause
Keyword(s):  
Electron Microscopy ◽  
Defect Formation ◽  
High Resolution Electron Microscopy ◽  
Dark Field ◽  
Silicon On Insulator ◽  
High Dose ◽  
Plan View ◽  
Weak Beam ◽  
Resolution Electron ◽  
Reduced Power Consumption

High dose oxygen implantation (SIMOX) has been a successful fabrication technology of silicon-on-insulator (SOI) material for CMOS circuits with reduced power consumption and higher operating speed. However, high density (~108 cm-2) of the through-thickness defects (TTD) in the top Si layer of SIMOX is one of the most serious problems. Hill et al. reported multiple implant/anneal method to remarkably reduce defect densities to <104 cm-2. In the multiple implant/anneal material, however, ~106 cm2 of the final dominant defects, including stacking fault pyramids (SFP) and the precipitate-dislocation complexes (PDC), still remained after high temperature annealing. In this work, the microstructures and formation mechanism of the final defects were studied by various TEM techniques.Silicon (100) wafers were sequentially triple implanted to doses of 6/6/6×l017 at 200kev and 620°C. After each implantation the wafers were held at 1000°C for 2 hours and annealed at 1325°C for 4 hours in argon ambient plus 5% oxygen. Cross-section (XTEM) and plan-view (PTEM) transmission electron microscopy specimens were examined by using a weak beam dark field (WBDF) and high resolution electron microscopy (HREM) techniques in JEM 2000FX and Topcon 002B operating at 200kev.

Effect of Annealing on the Structure of Buried SiO2 Layers Formed By Elevated Temperature High Dose Oxygen Implantation

1985 ◽  
Vol 53 ◽  
Author(s):  
S.J. Krause ◽  
C.O. Jung ◽  
S.R. Wilson ◽  
R.P. Lorigan ◽  
M.E. Burnham
Keyword(s):  
Single Crystal ◽  
Oxide Layer ◽  
Elevated Temperatures ◽  
Superficial Layer ◽  
Silicon On Insulator ◽  
High Dose ◽  
Threading Dislocations ◽  
Heater Temperature ◽  
Buried Oxide ◽  
Structural Differences

ABSTRACTOxygen has been implanted into Si wafers at high doses and elevated temperatures to form a buried SiO2 layer for use in silicon-on-insulator (SOI) structures. Substrate heater temperatures have been varied (300, 400, 450 and 500°C) to determine the effect on the structure of the superficial Si layer through a processing cycle of implantation, annealing, and epitaxial growth. Transmission electron microscopy was used to characterize the structure of the superficial layer. The structure of the samples was examined after implantation, after annealing at 1150°C for 3 hours, and after growth of the epitaxial Si layer. There was a marked effect on the structure of the superficial Si layer due to varying substrate heater temperature during implantation. The single crystal structure of the superficial Si layer was preserved at all implantation temperatures from 300 to 500°C. At the highest heater temperature the superficial Si layer contained larger precipitates and fewer defects than did wafers implanted at lower temperatures. Annealing of the as-implanted wafers significantly reduced structural differences. All wafers had a region of large, amorphous 10 to 50 nm precipitates in the lower two-thirds of the superficial Si layer while in the upper third of the layer there were a few threading dislocations. In wafers implanted at lower temperatures the buried oxide grew at the top surface only. During epitaxial Si growth the buried oxide layer thinned and the precipitate region above and below the oxide layer thickened for all wafers. There were no significant structural differences of the epitaxial Si layer for wafers with different implantation temperatures. The epitaxial layer was high quality single crystal Si and contained a few threading dislocations. Overall, structural differences in the epitaxial Si layer due to differences in implantation temperature were minimal.

Structure of twinned {113} defects in high-dose oxygen implanted silicon-on-insulator material

1991 ◽  
Vol 6 (4) ◽  
pp. 792-795 ◽  
Author(s):  
Supapan Visitserngtrakul ◽  
Stephen J. Krause ◽  
John C. Barry
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Oxide Layer ◽  
High Resolution Electron Microscopy ◽  
Silicon On Insulator ◽  
High Dose ◽  
Diamond Structure ◽  
Bulk Silicon ◽  
Coherent Interface ◽  
Resolution Electron

Conventional and high resolution electron microscopy (HREM) were used to study the structure of {113} defects in high-dose oxygen implanted silicon. The defects are created with a density of 1011 cm−2 below the buried oxide layer in the substrate region. The HREM images of the {113} defects are similar to the ribbon-like defects in bulk silicon. It is proposed that there is a third possible structure of the defects, in addition to coesite and/or hexagonal structures. Portions of some defects exhibit the original cubic diamond structure which is twinned across {115} planes. The atomic model shows that the {115} interface is a coherent interface with alternating five- and seven-membered rings and no dangling bonds.

Twinning Structure of {113} Defects in High-Dose Oxygen Implanted Silicon-on-Insulator Material.

1989 ◽  
Vol 163 ◽  
Author(s):  
S. Visitserngtrakul ◽  
J. Barry ◽  
S. Krause
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Oxide Layer ◽  
High Resolution Electron Microscopy ◽  
Silicon On Insulator ◽  
High Dose ◽  
Diamond Structure ◽  
Bulk Silicon ◽  
Coherent Interface ◽  
Resolution Electron

AbstractConventional and high resolution electron microscopy (HREM) were used to study the structure of the {113} defects in high-dose oxygen implanted silicon. The defects are created with a density of 1011 cm-2 below the buried oxide layer in the substrate region. The {113} defects are similar to the ribbon-like defects in bulk silicon. Our HREM observations show that two crystalline phases are present in the defect. Portions of the defects exhibit the original cubic diamond structure which is twinned across {115} planes. The atomic model shows that the {115} interface is a coherent interface with alternating five- and seven-membered rings and no dangling bonds.

Multiply faulted defects in high-current oxygen-implanted silicon-on-insulator

1989 ◽  
Vol 47 ◽  
pp. 606-607
Author(s):  
S. Visitserngtrakul
Keyword(s):  
Electron Microscopy ◽  
High Resolution Electron Microscopy ◽  
Beam Current ◽  
Silicon On Insulator ◽  
High Dose ◽  
High Current ◽  
Implantation Time ◽  
Resolution Electron ◽  
Beam Currents ◽  
Very High

High-dose oxygen implantation into silicon, SIMOX (separation by implantation of oxygen), is a leading technique for producing silicon-on-insulator (SOI) material. Most studies have examined SIMOX prepared with a traditional implanter, which has beam currents of 100 to 400 μA. Since the formation of SIMOX requires a very high dose of oxygen, typically one hundred times larger than the standard dopant implant doses, the process takes many hours. Recently, a high-current implanter has been developed for SIMOX fabrication, which produces a 40 mA beam current. However, the higher current density has not only shortened the implantation time, but also produced features not routinely observed in samples implanted at much lower currents. The study reported here used conventional transmission and high resolution electron microscopy (CTEM,HREM) to characterize microstructure and defects in SIMOX implanted at high currents.

Effect of Implantation Conditions on the Microstructure of High-Current, Oxygen Implanted Silicon-on-Insulator Material

1989 ◽  
Vol 157 ◽  
Author(s):  
S. Visitsemgtrakul ◽  
B.F. Cordts ◽  
S. Krause
Keyword(s):  
Defect Formation ◽  
Silicon Layer ◽  
High Resolution Electron Microscopy ◽  
Silicon On Insulator ◽  
Structural Development ◽  
Implantation Temperature ◽  
Resolution Electron ◽  
Significant Difference ◽  
New Type ◽  
Current Densities

ABSTRACTConventional and high resolution electron microscopy were used to study structural development in silicon-on-insulator material produced by oxygen implantation at temperatures of 525 to 700°C, doses of 0.3 to 1.8 × 1018 cm-2, and current densities of 1 and 10 mA/cm2. Implantation temperature has the strongest effect on the microstructure and defect formation, both in as-implanted and annealed material. In the top silicon layer of as-implanted SIMOX, oxygen bubbles form near the surface when the wafer temperature is ≥ 550°C. A new type of defect, the multiply faulted defect (MFD), has been observed at the upper edge of the implantation region with a density of 108 cm-2 in the samples implanted at the temperature of ≥ 600°C. As dose increases from 0.3 to 1.8 × 1018 cm-2, the bubbles grow larger and the trails of bubbles lengthen while the character and density of MFDs remain the same. A continuous buried oxide layer forms at doses ≥ 1.5 × 1018 cm2. No significant difference in structure is observed when a current-density increases from 1 to 10 mA/cm2.

High Resolution Electron Microscopy of Defects in High-Dose Oxygen Implanted Silicon-On-Insulator Material

1990 ◽  
Vol 183 ◽  
Author(s):  
S. Visitserngtrakul ◽  
C. O. Jung ◽  
B. F. Cordts ◽  
P. Roitman ◽  
S. J. Krause
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Oxide Layer ◽  
Stacking Faults ◽  
High Resolution Electron Microscopy ◽  
Silicon On Insulator ◽  
High Dose ◽  
Wafer Temperature ◽  
Buried Oxide ◽  
Resolution Electron

AbstractHigh resolution electron microscopy (HREM) has been used to study the atomic arrangement of defects formed during high-dose oxygen implantation of silicon-on-insulator material. The effect of implantation parameters of wafer temperature, dose, and current density were investigated. Wafer temperature had the largest effect on the type and character of the defects. Above the buried oxide layer in the top silicon layer, HREM revealed that microtwins and stacking faults were created during implantation from 350–450°C. From 450–550°C, stacking faults were longer and microtwinning was reduced. From 550–700°C, a new type of defect was observed which had lengths of 40 to 140 nm and consisted of several discontinuous stacking faults which were randomly spaced and separated by two to eight atomic layers. We have referred to them as “multiply faulted defects” (MFDs). Beneath the buried oxide layer in the substrate region, the defects observed included stacking faults and ( 113 ) defects. The results indicated that some parts of the ( 1131 defects can assume a cubic diamond structure created through a twin operation across (115) planes. Details of the structure and formation mechanisms of MFDs and other defects will be discussed.

Xenon ion irradiation of superconducting YBa2Cu3O7 thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 92-93
Author(s):  
H. Watanabe ◽  
B. Kabius ◽  
B. Roas ◽  
K. Urban
Keyword(s):  
Defect Formation ◽  
Ion Irradiation ◽  
High Resolution Electron Microscopy ◽  
Structural Disorder ◽  
Flux Lines ◽  
Pinning Effect ◽  
Magnetic Flux Lines ◽  
Resolution Electron ◽  
Radiation Induced ◽  
Induced Defects

Recently it was reported that the critical current density(Jc) of YBa2Cu2O7, in the presence of magnetic field, is enhanced by ion irradiation. The enhancement is thought to be due to the pinning of the magnetic flux lines by radiation-induced defects or by structural disorder. The aim of the present study was to understand the fundamental mechanisms of the defect formation in association with the pinning effect in YBa2Cu3O7 by means of high-resolution electron microscopy(HRTEM).The YBa2Cu3O7 specimens were prepared by laser ablation in an insitu process. During deposition, a substrate temperature and oxygen atmosphere were kept at about 1073 K and 0.4 mbar, respectively. In this way high quality epitaxially films can be obtained with the caxis parallel to the <100 > SrTiO3 substrate normal. The specimens were irradiated at a temperature of 77 K with 173 MeV Xe ions up to a dose of 3.0 × 1016 m−2.

Re-examining mechanisms of radiation damage in organic specimens

1990 ◽  
Vol 48 (4) ◽  
pp. 812-813
Author(s):  
David A. Armstrong ◽  
Suichu Luo ◽  
David C. Joy
Keyword(s):  
Mass Loss ◽  
Radiation Damage ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Limiting Factor ◽  
High Dose ◽  
X Ray ◽  
Resolution Electron ◽  
Significant Mass Loss ◽  
Significant Mass

Radiation damage to organic specimens is the major limiting factor in high resolution electron microscopy studies of biological systems. Electron beam irradiation compromises resolution by altering chemical microstructure, resulting in local mass loss and volume shrinkage in a specimen. All significant mass loss is thought to occur prior to a total incident dose of 50 electrons/ square angstrom If this is the case it is hard to reconcile the observation that images must be recorded at doses of less than 100 el/Å in order to avoid excessive mass loss and shrinkage while microanalytical (EDS and EELS) studies of the same tissue are routinely carried out at doses of 104 - 105el/Å2. Also, since most workers typically use either low dose (for imaging) or high dose (for microapalysis) there are apparently no studies in the literature which attempt to follow the process of radiation damage between these two extremes.We have chosen to investigate mass loss in polymer embedding resins such as are routinely used for TEM imaging as well as for X ray microanalytical applications.

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