193-Nm Excimer Laser-Assisted Etching of Polysilicon Films Using Cl2

1987 ◽  
Vol 101 ◽  
Author(s):  
Son Van Nguyen ◽  
S. Fridmann ◽  
J. Rembetski
Keyword(s):  
Gas Phase ◽  
Excimer Laser ◽  
Cross Section ◽  
Thermal Effects ◽  
Etch Rate ◽  
Absorption Cross ◽  
Molecular Flux ◽  
Polysilicon Films ◽  
193 Nm ◽  
Cl Atoms

ABSTRACT193-nm excimer laser-assisted etching of polysilicon was studied in the presence of CI2. Maximum etch rates of 1.25 Å/pulse were obtained for pressures of about 400 torr and fluences exceeding 400 mJ/(cm2-pulse). The etch rate increased with both fluence (100-550 mJ/(cm2-pulse)) and pressure (50-800 torr). An adsorptive etch mechanism similar to NF3 etching has been proposed, where Cl2 molecules diffuse to the surface, adsorb, and then react after absorbing laser radiation. This is consistent with photon and molecular flux considerations and the availability of reaction sites. Thermal effects where Cl2 molecules decompose to Cl atoms on “hot” polysilicon surfaces may assist this process, and appear to dominate under conditions of lower pressure (<400 torr) and higher fluence. Etching caused by the gas phase formation of Cl atoms is minimal due to the low Cl2 absorption cross section at 193 nm.Simple projection etching results showed that micron lines can be etched in polysilicon by use of this chemistry.

Excimer laser-assisted etching of polysilicon at 193 nm

1987 ◽  
Vol 2 (6) ◽  
pp. 895-901 ◽  
Author(s):  
M. D. Armacost ◽  
S. V. Babu ◽  
S. V. Nguyen ◽  
J. F. Rembetski
Keyword(s):  
Gas Phase ◽  
Excimer Laser ◽  
Cross Section ◽  
Thermal Effects ◽  
Etch Rate ◽  
Sem Analysis ◽  
Surface Roughening ◽  
193 Nm ◽  
Limiting Value ◽  
Scanning Electron

Excimer laser-assisted etching of polysilicon at 193 nm was studied in the presence of CF3Br, CF2Cl2, and NF3. In the presence of 193 nm radiation, CF3Br showed some propensity to etch polysilicon, while CF2Cl2 did not show any appreciable etching. In the presence of NF3, maximum etch rates of 0.6 Å/pulse were obtained for pressures greater than 500 Torr and fluences exceeding 200 mJ/(cm2 pulse). The etch rate increased with both fluences and pressure to a limiting value of 0.6 Å/pulse. An adsorptive etch mechanism was proposed, where NF3 molecules diffuse to the surface, adsorb, and then react after absorbing laser radiation. Thermal effects enhance this process and appear to dominate at lower pressures (<400 Torr) and higher fluences. Etching caused by the gas phase formation of F atoms is minimal due to the low absorption cross section of NF3 at 193 nm. Etching of submicron profiles in polysilicon was also examined. Polysilicon samples masked by patterned SiO2 were exposed to NF3 and 193 nm ArF radiation. Subsequent scanning electron microscopy (SEM) analysis demonstrated directional etching with some surface roughening.

Two-Photon Absorption Cross Section for Silane Under Pulsed Arf (193 nm) Excimer Laser Irradiation

1987 ◽  
Vol 101 ◽  
Author(s):  
C. Fuchs ◽  
E. Boch ◽  
E. Fogarassy ◽  
B. Aka ◽  
P. Siffert
Keyword(s):  
Excimer Laser ◽  
Cross Section ◽  
Absorption Cross Section ◽  
Incident Light ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Excimer Laser Irradiation ◽  
193 Nm

ABSTRACTWe have determined for the first time, the two-photon absorption cross-section of silane at 193 nm, by measuring directly the fraction of incident light absorbed in the gas phase during the irradiation with a pulsed ArF excimer laser.

scholarly journals Accurate laser measurements of ozone absorption cross-sections in the Hartley band

2014 ◽  
Vol 7 (8) ◽  
pp. 8067-8100 ◽  
Author(s):  
J. Viallon ◽  
S. Lee ◽  
P. Moussay ◽  
K. Tworek ◽  
M. Petersen ◽  
...  
Keyword(s):  
Gas Phase ◽  
Cross Section ◽  
Cross Sections ◽  
Radiative Forcing ◽  
Nitrogen Monoxide ◽  
Air Pollutant ◽  
Tropospheric Chemistry ◽  
Absorption Cross ◽  
Ozone Absorption ◽  
Hartley Band

Abstract. Ozone plays a crucial role in tropospheric chemistry, is the third largest contributor to greenhouse radiative forcing after carbon dioxide and methane and also a toxic air pollutant affecting human health and agriculture. Long-term measurements of tropospheric ozone have been performed globally for more than 30 years with UV photometers, all relying on the absorption of ozone at the 253.65 nm line of mercury. We have re-determined this cross-section and report a value of 11.27 × 10−18 cm2 molecule−1 with an expanded relative uncertainty of 0.84 %. This is lower than the conventional value currently in use and measured by Hearn in 1961 with a relative difference of 1.8%, with the consequence that historically reported ozone concentrations should be increased by 1.8%. In order to perform the new measurements of cross sections with reduced uncertainties, a system to generate pure ozone in the gas phase together with an optical system based on a UV laser with lines in the Hartley band, including accurate path length measurement of the absorption cell and a careful evaluation of possible impurities in the ozone sample by mass spectrometry and Fourier Transform Infrared spectroscopy was setup. This resulted in new measurements of absolute values of ozone absorption cross sections of 9.48 × 10−18, 10.44 × 10−18, and 11.07 × 10−18 cm2 molecule−1, with relative expanded uncertainties better than 0.6%, for the wavelengths (in vacuum) of 244.062, 248.32, and 257.34 nm respectively. The cross-section at the 253.65 nm line of mercury was determined by comparisons using a Standard Reference Photometer equipped with a mercury lamp as the light source. The newly reported value should be used in the future to obtain the most accurate measurements of ozone concentration, which are in closer agreement with non UV photometry based methods such as the gas phase titration of ozone with nitrogen monoxide.

Single-Crystal Silicon Etching Characteristics Using Excimer Laser Cℓ2 GAS

1983 ◽  
Vol 29 ◽  
Author(s):  
T. Arikado ◽  
M. Sekine ◽  
H. Okano ◽  
Y. Horiike
Keyword(s):  
Single Crystal ◽  
Gas Phase ◽  
Excimer Laser ◽  
Plasma Etching ◽  
Etch Rate ◽  
Single Crystal Silicon ◽  
Silicon Etching ◽  
Crystal Silicon ◽  
Direct Irradiation ◽  
P Type

ABSTRACTSingle-crystal Si etching characteristics using an excimer laser (308 nm, XeCℓ) in the Cℓ2 gas have been studied. In lightly doped n-type and p-type Si, the etch rate of (100) is higher than that of (111), thus the (111) sidewall appears clearly for the irradiation to (100), while both orientations show almost the same etch rates in n+-doped Si. The n-type Si is etched spontaneously even by photo-dissociated Cℓ radicals generated in the gas phase, but no p-type Si etching occurs without direct irradiation. In addition, both types of etch rate-dependence on sheet resistance demonstrate that the number of electrons in the conduction band plays an essential role in the Si etching. This fact supports the field-assisted mechanism in the plasma etching proposed by Winters.

A Comparison of the Gas Phase Processes Resulting from SiH4 and Si2H6 Photodissociation with a Pulsed ArF Excimer Laser

1988 ◽  
Vol 129 ◽  
Author(s):  
E. Boch ◽  
C. Fuchs ◽  
E. Fogarassy ◽  
P. Siffert
Keyword(s):  
Gas Phase ◽  
Excimer Laser ◽  
Laser Energy ◽  
Initial Pressure ◽  
Laser Pulses ◽  
Photon Absorption ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Deposition Yield ◽  
193 Nm

ABSTRACTWe present in this paper a comparison of the photodissociation processes of SiH4 and Si2H6 under pulsed excimer laser at 193 nm. The experimental curves of the gas composition as a function of laser energy density show that the dissociation of Si2H6 results from both one and two-photon absorption whereas SiH4 only absorbs two photons. The deposition yield of Si2H6 has also been determined as a function of the number of laser pulses or initial pressure. These experimental results show the establishment of a stationary state in the gas phase and prove the existence of reverse reactions in the disilane kinetic model. The photodissociation of Si2H6 under UV laser excitation (193 nm) presents, therefore, similar properties to those of SiH4.

Modeling of Silicon Deposition Yield at Low Temperature by ArF Excimer Laser Photolysis of Disilane

1992 ◽  
Vol 263 ◽  
Author(s):  
B. Fowler ◽  
S. Lian ◽  
S. Krishnan ◽  
C. Li ◽  
L. Jung ◽  
...  
Keyword(s):  
Gas Phase ◽  
Excimer Laser ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Film Deposition ◽  
Growth Surface ◽  
Phase Reaction ◽  
Gas Phase Reactions ◽  
Arf Excimer Laser ◽  
193 Nm

ABSTRACTNon-thermal Chemical Vapor Deposition (CVD) such as laser-enhanced photo-CVD of Si at low temperatures is important for Si-based heterostructures and doping superlattices. Growth kinetic models must be developed to allow these processes to be fully exploited. Intrinsic Si epitaxial layers were deposited at low substrate temperatures of 250-350ºC using the 193 nm output of an ArF excimer laser to directly dissociate Si2H6. The intrinsic film deposition rate can be described by a kinetic model that considers the gas phase reactions of the primary photolysis products and diffusion ofsilicon-bearing molecules to the growth surface. With the laser beam tangential to the substrate surface, growth rates as a function of beam-to-substrate distance have been characterized and indicate that very little gas phase reaction occurs for the dominant Si growth precursor. In order for intrinsic film deposition to result solely from Si2H6 photolysis products, a sticking coefficient ≥ 0.6 must be assigned to the dominant growth precursor in order to fit the observed yield of Si deposited in the films, indicating that the dominant growth precursor in 193 nm Si2H6 photolysis is perhaps H2SiSiH2.

X-Ray Photoemission Investigation of Excimer Laser Induced Etching of InP

1989 ◽  
Vol 158 ◽  
Author(s):  
R. Matz ◽  
J. Meiler ◽  
D. Haarer
Keyword(s):  
Gas Phase ◽  
Excimer Laser ◽  
Spatial Resolution ◽  
Etch Rate ◽  
Large Area ◽  
X Ray ◽  
Resolution Capability ◽  
Fundamental Understanding ◽  
Arf Excimer Laser ◽  
Laser Induced Etching

ABSTRACTArF excimer laser induced etching of InP in various etch gases (HBr, HCI, CI2) is discussed with regard to its spatial resolution capability. X-ray photoemission spectra and large-area etch rate measurements published before lead to fundamental understanding and interpretation of the characteristics of etched test structures. HBr and HCI require gas phase photodissociation. CI2' in contrast, has the advantage to react spontaneously.

Sign in / Sign up

Export Citation Format

Share Document