Electron cyclotron resonance etching characteristics of GaN in plasmas with and without hydrogen

1995 ◽  
Vol 395 ◽  
Author(s):  
L. Zhang ◽  
J. Ramer ◽  
J. Brown ◽  
K. Zheng ◽  
L.F. Lester ◽  
...  
Keyword(s):  
Cyclotron Resonance ◽  
Etch Rate ◽  
Electron Cyclotron Resonance ◽  
Defect Density ◽  
Dry Etching ◽  
Electron Cyclotron ◽  
Ecr Plasma ◽  
Good Surface ◽  
Dc Bias ◽  
Gate Recess

ABSTRACTElectron cyclotron resonance (ECR) plasma etching characteristics of gallium nitride (GaN) are investigated using low pressure (4-10 mTorr) SiCl4/Ar and Cl2/H2/Ar ECR discharges. The purpose of this effort is to develop a dry etching process for making laser mirrors on GaN and to examine dry etching processes of GaN that do not require hydrogen, which is known to cause carrier compensation in GaN. The etch rate is found to increase near-linearly with increasing DC bias, and a minimum DC bias of 100V is required to initiate etching in SiCl4/Ar. We have also found that the material quality significantly affects the etch rate. The latter decreases with x-ray rocking curve half-width and increases with defect density. A reasonable etch rate of 660Ǻ/min and good surface morphologies obtained in SiCl/Ar ECR etching make this process suitable for gate recess of an FET. An etch rate of 5270Ǻ/min has been achieved in Cl2/H2/Ar plasmas. This is the highest reported etch rate of GaN so far. The smooth and vertical etch sidewalls (etch to mask selectivity of 16 is obtained) make this process promising for dry-etched laser mirrors on GaN.

In-Situ Ellipsometric Monitoring of the Electron Cyclotron Resonance Etching of Diamond-Like Carbon

1994 ◽  
Vol 349 ◽  
Author(s):  
N.J. Ianno ◽  
S. Ahmer ◽  
S. Pittal ◽  
John A. Woollam
Keyword(s):  
Cyclotron Resonance ◽  
Etch Rate ◽  
Electron Cyclotron Resonance ◽  
Carbon Films ◽  
Electron Cyclotron ◽  
Diamond Like Carbon ◽  
Strong Function ◽  
Dc Bias ◽  
Input Variables

ABSTRACTThe electron cyclotron resonance (ECR) etching of diamond-like carbon films in an oxygen plasma has been studied. The input variables were flow rate, pressure, power, and bias, while the output parameters were etch rate, and uniformity. In-situ ellipsometry, performed at 44 wavelengths simultaneously, was employed to monitor the etch process in real time. We will show that DLC films can be etched without an applied bias, but the application of an rf induced dc bias greatly enhances etch uniformity. Further, the etch rate is a strong function of the bandgap of the DLC film.

In-Situ Monitoring by Mass Spectrometry for GaAs Etched with An Electron Cyclotron Resonance Source

1993 ◽  
Vol 324 ◽  
Author(s):  
D. J. Kahaian ◽  
S. W. Pang
Keyword(s):  
Mass Spectrometry ◽  
Cyclotron Resonance ◽  
Etch Rate ◽  
Electron Cyclotron Resonance ◽  
Diagnostic Technique ◽  
Electron Cyclotron ◽  
In Situ Monitoring ◽  
Rf Power ◽  
Dc Bias

AbstractQuadrupole mass spectrometry (QMS) has been used as an in-situ diagnostic technique for GaAs etched with an electron cyclotron resonance source. Changes in the detected signal intensities for reactive species and etch products have been related to corresponding changes in the etch rate as several process parameters were varied. The detected 75As+ and to a lesser degree, 35C1+ and 70C12+, were observed to follow etch rate as microwave power, rf power, source to sample distance, temperature, and pressure were varied. The self-induced dc bias (IVdcl) determines the etch rate dependence on etch time. The time delay before saturation of the monitored 75As+ signal corresponding to a constant etch rate is inversely proportional to IVdcl. The addition of N2/O2 in a 4:1 ratio to constitute 15% of the total discharge resulted in a 95% decrease in the intensity of the monitored 75As+ signal. The measured etch rate decreased by 75%.

Dependence of the a-Si:H Defect Density of States on the Magnetic Field Profile of an Electron Cyclotron Resonance Microwave Plasma

1992 ◽  
Vol 258 ◽  
Author(s):  
F.S. Pool ◽  
J.M. Essick ◽  
Y.H. Shing ◽  
R.T. Mather
Keyword(s):  
Magnetic Field ◽  
Density Of States ◽  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Microwave Plasma ◽  
Defect Density ◽  
Electron Cyclotron ◽  
Field Profile ◽  
Magnetic Field Profile ◽  
The Magnetic Field

ABSTRACTThe magnetic field profile of an electron cyclotron resonance (ECR) microwave plasma was systematically altered to determine subsequent effects on a-Si:H film quality. Films of a-Si:H were deposited at pressures of 0.7 mTorr and 5 mTorr with a H2/SiH4 ratio of approximately three. The mobility gap density of states ND, deposition rate and light to dark conductivity were determined for the a-Si:H films. This data was correlated to the magnetic field profile of the plasma, which was characterized by Langmuir probe measurements of the ion current density. By variation of the magnetic field profile ND could be altered by more than an order of magnitude, from 1×1016 to 1×1017 at 0.7 mTorr and 1×1016 to 5×1017 at 5 mTorr. Two deposition regimes were found to occur for the conditions of this study. Highly divergent magnetic fields resulted in poor quality a-Si:H, while for magnetic field profiles defining a more highly confined plasma, the a-Si:H was of device quality and relatively independent of the magnetic field configuration.

Hydrogen in Dielectric Film Formation From an Electron Cyclotron Resonance Plasma

1991 ◽  
Vol 235 ◽  
Author(s):  
J. C. Barbour ◽  
H. J. Stein
Keyword(s):  
Cyclotron Resonance ◽  
Electron Cyclotron Resonance ◽  
Ion Irradiation ◽  
Film Formation ◽  
Ion Beam ◽  
Electron Cyclotron ◽  
Elastic Recoil ◽  
Elastic Recoil Detection ◽  
Ecr Plasma ◽  
The Stability

ABSTRACTThe incorporation of hydrogen into silicon nitride films grown downstream from an electron cyclotron resonance (ECR) plasma decreased rapidly with increasing substrate temperature (100–600°C). Fourier transform infra-red (FTIR) spectroscopy showed that the hydrogen in the as-grown material was primarily bonded to nitrogen. However, an applied bias of -200 V caused an increase in the number of Si-H bonds relative to N-H bonds, as a result of increased ion-beam damage. In addition, ion irradiation of an as-grown film with 175 keV Ar+ at room temperature showed that H transferred from N-H bonds to Si-H bonds without a loss of H. Elastic recoil detection (ERD) and FTIR of thermally annealed films showed that the stability of H incorporated during deposition increased with deposition temperature, and that the N-H bond was more stable than the Si-H bond above 700°C. Deuterium plasma treatments, at 600°C, of annealed films caused isotopic substitution with a conservation of bonds. Therefore, hydrogen loss from annealed films is apparently accompanied by a reduction in dangling bonds.

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