Publications

Displaying 1 - 25 of 41

Response to "Comment on 'The effects of radio-frequency bias on electron density in an inductively coupled plasma reactor' "

October 20, 2022

Author(s)

Mark Sobolewski

The rf-bias-induced decreases in plasma electron density observed by us [J. Appl. Phys. 102, 113302 (2007)] and others [Fox-Lyon et al., J. Vac. Sci. Technol. A 32, 030601 (2014)] are better explained by changes in gas composition, rather than neutral gas

In situ measurement of electron emission yield and elastic reflection coefficient at silicon dioxide surfaces exposed to argon plasmas

February 25, 2021

Author(s)

Mark Sobolewski

Plasma simulations require accurate yield data to predict the electron flux that is emitted when plasma-exposed surfaces are bombarded by energetic particles. One can measure yields directly using particle beams, but it is impractical to create a separate

Ion velocities in the presheath of electronegative, radio-frequency plasmas measured by low-energy cutoff

July 13, 2016

Author(s)

Mark A. Sobolewski

Simple kinematic considerations indicate that, under certain conditions in radio-frequency (rf) plasmas, the amplitude of the low-energy peak in ion energy distributions (IEDs) measured at an electrode depends sensitively on ion velocities upstream, at the

Power coupling and utilization efficiencies of silicon-depositing plasmas in mixtures of H2, SiH4, Si2H6, and Si3H8

June 24, 2014

Author(s)

Mark A. Sobolewski

Adding Si2H6 or Si3H8 additives to SiH4/H2 discharges increases the growth rates for thin films of microcrystalline and amorphous silicon, but the reasons for this increase are not well understood. To better distinguish the chemical and physical from

Origin of Electrical Signals for Plasma Etching Endpoint Detection: Comparison of Endpoint Signals and Electron Density

July 23, 2012

Author(s)

Mark A. Sobolewski, David L. Lahr

Electrical signals are used for endpoint detection in plasma etching, but the origin of the electrical changes observed at endpoint is not well understood. As an etch breaks through one layer and exposes an underlayer, the fluxes and densities of etch

Origin of Electrical Signals for Plasma Etching Endpoint Detection

November 18, 2011

Author(s)

Mark A. Sobolewski

Electrical signals are used for endpoint detection in plasma etching, but the origin of the electrical changes observed at endpoint is not known. They may be caused by changes in the gas-phase densities of etch products and reactants or by changes in

Real-Time Monitoring of Ion Energy and Ion Flux in Plasma Reactors Using RF Current and Voltage Measurements

October 16, 2008

Author(s)

Mark Sobolewski

A non-invasive, non-perturbing method for monitoring ion current and ion kinetic energy that is suitable for use during actual processing in industrial plasma reactors has been developed and validated. The method has been used to monitor the drift in ion

Validated Sheath Model for Radio-Frequency-Biased, High-Density Plasmas

October 16, 2008

Author(s)

Mark Sobolewski

A model is proposed for sheaths in high-density plasma discharges, with radio-frequency bias applied at frequencies (omega) comparable to (omega sub i), the ion plasma frequency at the edge of the sheath. The model treats ion dynamics using fluid equations

Electron heating in rf-biased, inductively coupled plasmas

July 15, 2008

Author(s)

Mark A. Sobolewski, J. -. Kim

The effect of radio-frequency (rf) bias on electron density in an inductively coupled plasma reactor was measured using a wave cutoff probe, in Ar, CF4, and Ar/CF4 mixtures. At low source powers, we observed an increase in plasma electron density caused by

Noninvasive monitoring of ion current and ion energy during plasma processing

July 15, 2008

Author(s)

Mark A. Sobolewski

A technique has been developed for noninvasive monitoring of ion energy and ion current in plasma reactors. The technique relies on measurements of the applied rf bias current and voltage, which are interpreted using a fundamental, physical model of the

Effects of Wafer Impedance on the Monitoring and Control of Ion Energy in Plasma Reactors

September 15, 2006

Author(s)

Mark A. Sobolewski

Real-Time, Noninvasive Monitoring of Ion Energy and Ion Current at a Wafer Surface During Plasma Etching

September 1, 2006

Author(s)

Mark A. Sobolewski

A noninvasive, non-perturbing technique for real-time monitoring of ion energy distributions and total ion current at a wafer surface during plasma processing has been used to monitor rapid changes in CF4/Ar etching plasmas in an inductively coupled, rf

2-D Imaging of Temperature in CF 4 Plasmas

April 1, 2005

Author(s)

Kristen L. Steffens, Mark A. Sobolewski

Two-dimensional maps of rotational temperature were determined in CF4 plasmas using planar laser-induced fluorescence of CF. Experiments were performed in a capacitively-coupled, parallel plate plasma reactor at pressures from 200mTorr (26.7Pa) to 800mTorr

Noninvasive Monitoring of Ion Energy Drift in an Inductively Coupled Plasma Reactor

February 1, 2005

Author(s)

Mark A. Sobolewski

A non-invasive method for monitoring ion current and ion kinetic energy has been used to monitor drift in an inductively coupled, rf-biased plasmareactor. The technique detects a slow decrease in ion current over time caused by the deposition of a

A Technique for Temperature Mapping in Fluorocarbon Plasmas Using Planar Laser-Induced Fluorescence of CF

July 1, 2004

Author(s)

Kristen L. Steffens, Mark A. Sobolewski

Planar laser-induced fluorescence (PLIF) measurements of CF A2S+ - X2P (1,0) were used to determine two-dimensional maps of rotational temperature in CF4 plasmas. Measured rotational temperatures are expected to be in equilibrium with the gas temperature

Monitoring Sheath Voltages and Ion Energies in High-Density Plasmas Using Noninvasive Radio-Frequency Current and Voltage Measurements

September 1, 2003

Author(s)

Mark A. Sobolewski

To obtain optimal results from plasma processing, the energy of ions incident on substrate wafers must be carefully controlled. Such control has been difficult to achieve, however, because no practical method exists for monitoring the energy distributions

Effect of Changing the Electrode Gap on the Spatial and Electrical Properties of O 2 /CF 4 Plasmas

January 1, 2003

Author(s)

Kristen L. Steffens, Mark A. Sobolewski

Planar laser-induced fluorescence (PLIF) measurements were made to determine 2-D spatial maps of CF2 density as a chemical marker of plasma uniformity in 9% O2/91% CF4 chamber-cleaning plasmas. Measurements were made in the capacitively-coupled Gaseous

Measurements and modeling of ion energy distribution in high-density, radio-frequency biased CF4 discharges

May 1, 2002

Author(s)

Mark A. Sobolewski, Yicheng Wang, Amanda N. Goyettes

Measurements and Modeling of Ion Energy Distributions in High-Density, Radio-Frequency Biased CF 4 Discharges

May 1, 2002

Author(s)

Mark A. Sobolewski, Yicheng Wang, A N. Goyette

Models of ion dynamics in radio-frequency (rf) biased, high-density plasma sheaths are needed to predict ion bombardment energies in plasma simulations. To test these models, we have measured ion energy distributions (IEDs) in pure CF 4 discharges at 1.33

Measuring the Ion Current in High-Density Plasmas Using Radio-Frequency Current and Voltage Measurements

September 1, 2001

Author(s)

Mark A. Sobolewski

The total current or flux of ions striking the substrate is an important parameter that must be tightly controlled during plasma processing. Several methods have recently been proposed for monitoring the ion current in situ. These methods rely on passive

Investigation and Control of Spatial Characteristics of Chamber-Cleaning Plasmas

February 1, 2001

Author(s)

Kristen L. Steffens, Mark A. Sobolewski

Planar laser-induced fluorescence (PLIF) measurements were made to determine 2-D spatial maps of CF2 density as a chemical marker of plasma uniformity in 9%O2/91%CF4 chamber-cleaning plasmas. Measurements were made in the capacitively-coupled Gaseous

Monitoring Ion Current and Ion Energy During Plasma Processing Using Radio-Frequency Current and Voltage Measurements

February 1, 2001

Author(s)

Mark A. Sobolewski

To obtain optimal results from plasma processing, the energy of ions incident on the substrate and their current or flux must be carefullymonitored and controlled. Although several common diagnostic techniques can be used to measure ion current and ion

Sheath Model for Radio-Frequency-Biased, High-Density Plasmas, Valid for all O/O Iota

December 1, 2000

Author(s)

Mark A. Sobolewski

A model is proposed for sheaths in high-density discharges, with radio-frequency (rf) bias applied at frequencies ω comparable to ω i, the ion plasma frequency at the edge of the sheath. The model treats ion dynamics using fluid equations, including all

Electrical Control of Plasma Spatial Uniformity Investigated by Planar Laser-Induced Fluorescence

December 1, 1999

Author(s)

Kristen L. Steffens, Mark A. Sobolewski

Electrical Control of the Spatial Uniformity of Reactive Species in Plasmas

December 1, 1999

Author(s)

Mark A. Sobolewski, Kristen L. Steffens

We report a new method for controlling the spatial distribution of reactive chemical species in a parallel-plate reactor, by means of a variable-impedance load placed between the unpowered electrode and ground. The technique was demonstrated in 89% CF(sub4

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