Reactions of Photogenerated CF2 and CF3 on Silicon and Silicon Oxide Surfaces

1988 ◽  
Vol 129 ◽  
Author(s):  
John Langan ◽  
J.A. Shorter ◽  
Xu Xin ◽  
J.I. Steinfeld
Keyword(s):  
Silicon Surface ◽  
Silicon Oxide ◽  
Single Crystal Silicon ◽  
Laser Photolysis ◽  
Oxide Surfaces ◽  
Ion Sputtering ◽  
Dissociative Chemisorption ◽  
Crystal Silicon ◽  
Infrared Multiple Photon Dissociation ◽  
Argon Ion

ABSTRACTWe have investigated the reactions of neutral fluorocarbon fragments, generated by laser photolysis of suitable precursors, with single-crystal silicon and thermally deposited silicon oxide surfaces. CF3 free radicals are generated by infrared multiple-photon dissociation of C2F6. While CF3 undergoes dissociative chemisorption on Si, it adsorbs very little on annealed SiO2 surfaces, and even on ion-damaged oxide surfaces, CF3 adsorbs but does not undergo transfer of fluorine from the fluorocarbon to surface silicon atoms. CF2, produced by excimer-laser photolysis of C2F4, is adsorbed on SiO2 surfaces. As with CF3, no transfer of fluorine from carbon to silicon is observed, even after argon-ion sputtering or ultraviolet irradiation of the surface. These measurements have been extended to NF3; this species chemisorbs and dissociates on a silicon surface, but even a monolayer of oxide is sufficient to block this process. A simple model based on the relative strengths of C-F, N-F, Si-F, Si-C, Si-O, and Si-N bonds appears to account for the observed behavior of CF3, CF2, and NF3 species on silicon and silicon oxide surfaces. In other cases, however, a barrier appears to be implicated in the chemisorption process.

Silicon Surface Morphologies after Femtosecond Laser Irradiation

MRS Bulletin ◽  
2006 ◽  
Vol 31 (8) ◽  
pp. 626-633 ◽  
Author(s):  
Brian R. Tull ◽  
James E. Carey ◽  
Eric Mazur ◽  
Joel P. McDonald ◽  
Steven M. Yalisove
Keyword(s):  
Femtosecond Laser ◽  
Silicon Surface ◽  
Sulfur Hexafluoride ◽  
Silicon Oxide ◽  
Single Crystal Silicon ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Femtosecond Laser Irradiation ◽  
Crystal Silicon ◽  
Surface Morphologies

AbstractIn this article, we present summaries of the evolution of surface morphology resulting from the irradiation of single-crystal silicon with femtosecond laser pulses. In the first section, we discuss the development of micrometer-sized cones on a silicon surface irradiated with hundreds of femtosecond laser pulses in the presence of sulfur hexafluoride and other gases. We propose a general formation mechanism for the surface spikes. In the second section, we discuss the formation of blisters or bubbles at the interface between a thermal silicon oxide and a silicon surface after irradiation with one or more femtosecond laser pulses. We discuss the physical mechanism for blister formation and its potential use as channels in microfluidic devices.

A Current Conduction Mechanism in Laser Recrystallized Silicon Metal-Oxide-Semiconductor Transistors

1983 ◽  
Vol 23 ◽  
Author(s):  
Han-Sheng Lee
Keyword(s):  
Conduction Mechanism ◽  
Single Crystal Silicon ◽  
Silicon Films ◽  
Oxide Semiconductor ◽  
Silicon Substrates ◽  
Mos Transistors ◽  
Crystal Silicon ◽  
Ion Laser ◽  
Argon Ion ◽  
A Current

ABSTRACTN-channel MOS transistors were fabricated on silicon films that had been recrystallized by an argon ion laser at different power levels. These transistors showed electrical characteristics similar, but somewhat inferior to those devices fabricated on single crystal silicon substrates. These differences are attributed to the presence of trapping states at the grain boundaries of the crystallites in the recrystallized silicon. A coulombic scattering model is presented to explain these differences. In the case of films annealed at low laser power, an additional factor of nonuniform trap state distribution is invoked to explain device characteristics. This model provides an adequate explanation for the observed transport properties of transistors fabricated from recrystallized silicon films.

Formation of ultrathin iron silicide layers on the single-crystal silicon surface

2006 ◽  
Vol 48 (10) ◽  
pp. 2016-2020 ◽  
Author(s):  
M. V. Gomoyunova ◽  
D. E. Malygin ◽  
I. I. Pronin
Keyword(s):  
Single Crystal ◽  
Silicon Surface ◽  
Iron Silicide ◽  
Single Crystal Silicon ◽  
Crystal Silicon

Rie-Induced Damage to Single Crystal Silicon Monitored with Nondestructive Thermal Waves

1986 ◽  
Vol 68 ◽  
Author(s):  
Patrice Geraghty ◽  
W. Lee Smith
Keyword(s):  
Process Parameters ◽  
Plasma Etching ◽  
Thermal Wave ◽  
Silicon Surface ◽  
Single Crystal Silicon ◽  
Thermal Waves ◽  
Process Variables ◽  
Crystal Silicon ◽  
Laser Probe ◽  
Damage Level

AbstractA method is presented to nondestructively monitor damage in silicon caused by reactive-ion or plasma etching on actual product wafers or test wafers immediately following the etch step.Data is taken on product wafers by scanning the 1-micron laser probe spot across and along the bottom of RIE-etched trenches.The onset of silicon damage brings a marked increase to the thermal wave (TW) signal: as the RIE bias voltage was increased from -60 volts to -250 volts, the TW signal increased monotonically by 1230%.The effects of other RIE process parameters on the damage level were also measured.This study allowed the RIE process variables to be adjusted to minimize damage to the silicon surface.

Highly oriented, textured diamond films on silicon via bias-enhanced nucleation and textured growth

1993 ◽  
Vol 8 (6) ◽  
pp. 1334-1340 ◽  
Author(s):  
B.R. Stoner ◽  
S.R. Sahaida ◽  
J.P. Bade ◽  
P. Southworth ◽  
P.J. Ellis
Keyword(s):  
Silicon Surface ◽  
Diamond Films ◽  
Single Crystal Silicon ◽  
Film Surface ◽  
Potential Effect ◽  
Structural Defects ◽  
Silicon Substrates ◽  
Electrical Characteristics ◽  
Crystal Silicon ◽  
Nucleation Stage

Highly oriented diamond films were grown on single-crystal silicon substrates. Textured films were first nucleated by a two-step process that involved the conversion of the silicon surface to an epitaxial SiC layer, followed by bias-enhanced nucleation. The nucleation stage, which produced a partially oriented diamond film, was immediately followed by a (100) textured growth process, thus resulting in a film surface where approximately 100% of the grains are epitaxially oriented relative to the silicon substrate. The diamond films were characterized by both SEM and Raman spectroscopy. Structural defects in the film are discussed in the context of their potential effect on the electrical characteristics of the resulting film.

Tissue Compatibility of Silicon Microfabricated Probes Inserted into the Brain

1997 ◽  
Vol 3 (S2) ◽  
pp. 289-290
Author(s):  
J. N. Turner ◽  
William Shain ◽  
D. H. Szarowski ◽  
M. Anderson ◽  
S. Martins ◽  
...  
Keyword(s):  
Silicon Oxide ◽  
Single Crystal Silicon ◽  
Tissue Reaction ◽  
Crystal Silicon ◽  
Silicon Oxide Layer ◽  
Disease States ◽  
Large Numbers ◽  
The Central Nervous System ◽  
High Level ◽  
The Brain

The application of nano- and microfabricated devices based on silicon electronics technology is an emerging interdisciplinary area combining engineering and biology. The placement of electrically active probes in damaged or diseased tissues of the central nervous system could have enormous impact on the health and quality of life of large numbers of individuals by restoring lost function, or by treating or controlling disease states. Such probes have been fabricated at a high level of engineering sophistication. Unfortunately, when inserted into the brain a tissue reaction is initiated forming a scar that surrounds and electrically isolates the probe within a few weeks. This reaction is thought to primarily involve glial cells, and is undoubtedly dominated by the bulk surface of the probes which have a silicon oxide layer on top of single crystal silicon.Model probes (Fig. 1) were microfabricated by photolithography with a 1×1mm tab used for gripping and inserting probes.

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