scholarly journals Plasma Chemistry Dependent ECR Etching of GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
R. J. Shul ◽  
C. I. H. Ashby ◽  
D. J. Rieger ◽  
A. J. Howard ◽  
S. J. Pearton ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Plasma Chemistry ◽  
Auger Spectroscopy ◽  
Near Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Opposite Trend ◽  
Etch Rates

ABSTRACTElectron cyclotron resonance (ECR) etching of GaN in Cl2/H2/Ar, Cl2/SF6/Ar, BCl3/H2Ar and BCl3/SF6/Ar plasmas is reported as a function of percent H2 and SF6. GaN etch rates were found to be 2 to 3 times greater in Cl2/H2/Ar discharges than in BCl3/H2/Ar discharges independent of the H2 concentration. In both discharges, the etch rates decreased as the H2 concentration increased above 10%. When SF6 was substituted for H2, the GaN etch rates in BCl3-based plasmas were greater than those for the Cl2-based discharges as the SF6 concentration increased. GaN etch rates were greater in Cl2/H2/Ar discharges as compared to Cl2/SF6/Ar discharges whereas the opposite trend was observed for BCl3,-based discharges. Variations in surface morphology and near-surface stoichiometry due to plasma chemistries were also investigated using atomic force microscopy and Auger spectroscopy, respectively.

Ecr Etching of GaP, GaAs, InP, and InGaAs in Cl2/Ar, Cl2/N2, BCl3/Ar, and BCl3/N2

1996 ◽  
Vol 421 ◽  
Author(s):  
R. J. Shul ◽  
A. G. Baca ◽  
D. J. Rieger ◽  
H. Hou ◽  
S. J. Pearton ◽  
...  
Keyword(s):  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Plasma Chemistry ◽  
Electron Cyclotron ◽  
Wide Range ◽  
Etch Rates

AbstractElectron cyclotron resonance (ECR) etching of GaP, GaAs, InP, and InGaAs are reported as a function of percent chlorine-containing gas for Cl2/Ar, Cl2/N2, BCl3/Ar, and BCl3/N2 plasma chemistries. GaAs and GaP etch rates were faster than InP and InGaAs, independent of plasma chemistry due to the low volatility of the InClx, etch products. GaAs and GaP etch rates increased as %Cl2 was increased for Cl2/Ar and Cl2/N2 plasmas. The GaAs and GaP etch rates were much slower in BCl3-based plasmas due to lower concentrations of reactive Cl, however enhanced etch rates were observed in BCl3/N2 at 75% BCl3. Smooth etched surfaces were obtained over a wide range of plasma chemistries.

scholarly journals Electron transfer between anatase TiO2 and an O2 molecule directly observed by atomic force microscopy

2017 ◽  
Vol 114 (13) ◽  
pp. E2556-E2562 ◽  
Author(s):  
Martin Setvin ◽  
Jan Hulva ◽  
Gareth S. Parkinson ◽  
Michael Schmid ◽  
Ulrike Diebold
Keyword(s):  
Atomic Force Microscopy ◽  
Electron Transfer ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Near Surface ◽  
Force Microscopy ◽  
Atomic Force

Activation of molecular oxygen is a key step in converting fuels into energy, but there is precious little experimental insight into how the process proceeds at the atomic scale. Here, we show that a combined atomic force microscopy/scanning tunneling microscopy (AFM/STM) experiment can both distinguish neutral O2 molecules in the triplet state from negatively charged (O2)− radicals and charge and discharge the molecules at will. By measuring the chemical forces above the different species adsorbed on an anatase TiO2 surface, we show that the tip-generated (O2)− radicals are identical to those created when (i) an O2 molecule accepts an electron from a near-surface dopant or (ii) when a photo-generated electron is transferred following irradiation of the anatase sample with UV light. Kelvin probe spectroscopy measurements indicate that electron transfer between the TiO2 and the adsorbed molecules is governed by competition between electron affinity of the physisorbed (triplet) O2 and band bending induced by the (O2)− radicals. Temperature–programmed desorption and X-ray photoelectron spectroscopy data provide information about thermal stability of the species, and confirm the chemical identification inferred from AFM/STM.

Spectroscopic Ellipsometry Study of HgCdTe Epilayer Surfaces During Electron Cyclotron Resonance Plasma Etching

1996 ◽  
Vol 450 ◽  
Author(s):  
J. N. Johnson ◽  
J. H. Dinan ◽  
K. M. Singley ◽  
M. Martinka ◽  
B. Johs
Keyword(s):  
Plasma Etching ◽  
Photoelectron Spectroscopy ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Surface Region ◽  
Auger Spectroscopy ◽  
Electron Cyclotron ◽  
Ex Situ ◽  
Process Conditions ◽  
Near Surface

ABSTRACTSpectroscopie ellipsometry has been used to monitor optical characteristics of HgCdTe surfaces during plasma etching in an electron cyclotron resonance reactor. Commonly used process conditions were found to induce changes in the ellipsometric parameters Δ and φ. A model was constructed to account for these changes in terms of process-induced roughness and mercury depleted sub-surface layers An independent characterization of the near-surface region was earned out ex situ after etching using Auger spectroscopy and x-ray photoelectron spectroscopy. Plasma process parameters were varied to isolate their influence on surface conditions and a set of parameters is given for which changes are minimized.

Sign in / Sign up

Export Citation Format

Share Document