Patterning of GaN in High-Density Cl2- and BCl3-Based Plasmas

1997 ◽  
Vol 468 ◽  
Author(s):  
R. J. Shul ◽  
R. D. Briggs ◽  
J. Han ◽  
S. J. Pearton ◽  
J. W. Lee ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Chemical Nature ◽  
Photonic Devices ◽  
High Density ◽  
Low Degree ◽  
Patterning Technique ◽  
High Bond ◽  
Dc Bias ◽  
Etch Rates ◽  
Surface Morphologies

ABSTRACTFabrication of group-Ill nitride electronic and photonic devices relies heavily on the ability to pattern features with anisotropie profiles, smooth surface morphologies, etch rates often exceeding 0.5 μm/min, and a low degree of plasma-induced damage. Patterning these materials has been especially difficult due to their high bond energies and their relatively inert chemical nature as compared to other compound semiconductors. However, high-density plasma etching has been an effective patterning technique due to ion fluxes which are 2 to 4 orders of magnitude higher than conventional RIE systems. GaN etch rates as high as -1.3 μm/min have been reported in ECR generated ICI plasmas at -150 V dc-bias. In this study, we report high-density GaN etch results for ECR- and ICP-generated plasmas as a function of Cl2- and BCl3-based plasma chemistries.

scholarly journals Dry Etching of III-V Nitrides

1995 ◽  
Vol 395 ◽  
Author(s):  
S. J. Pearton ◽  
R. J. Shul ◽  
G. F. McLane ◽  
C. Constantine
Keyword(s):  
Plasma Etching ◽  
Dry Etching ◽  
Ion Density ◽  
Chemical Inertness ◽  
Order Of Magnitude ◽  
High Bond ◽  
Bond Strengths ◽  
Dc Bias ◽  
Etch Rates

ABSTRACTThe chemical inertness and high bond strengths of the III-V nitrides lead to slower plasma etching rates than for more conventional III-V semiconductors under the same conditions. High ion density conditions (>3×1011cm−3) such as those obtained in ECR or magnetron reactors produce etch rates up to an order of magnitude higher than for RIE, where the ion densities are in the 109 cm−3 range. We have developed smooth anisotropic dry etches for GaN, InN, AlN and their alloys based on Cl2/CH4/H2/Ar, BCl3/Ar, Cl2/H2, C12/SF6, HBr/H2 and HI/H2 plasma chemistries achieving etch rates up to ∼4,000Å/min at moderate dc bias voltages (≤-150V). Ion-induced damage in the nitrides appears to be less apparent than in other III-V’s. One of the key remaining issues is the achievement of high selectivities for removal of one layer from another.

HI/H2 ECR Plasma Etching of III-V Semiconductors

1992 ◽  
Vol 268 ◽  
Author(s):  
S. J. Pearton ◽  
U. K. Chakrabarti ◽  
A. Katz ◽  
F. Ren ◽  
T. R. Fullowan ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Electron Spectroscopy ◽  
Dry Etching ◽  
Hydrogen Passivation ◽  
Near Surface ◽  
Ecr Plasma ◽  
Order Of Magnitude ◽  
Polymer Deposition ◽  
Etch Rates ◽  
Surface Morphologies

ABSTRACTHI/H2/Ar discharges are shown to be universal etchants for rn-V semiconductors, giving rise to highly anisotropic features with smooth surface morphologies. At loy dc self bia:s (-100V) and low pressure (1 mTorr), etch rates for all III-V materials of >2000Å min−1 are possible for high HI percentages in the discharges, whereas rates greater than 1 Åm min−1 are obtained at higher pressures and dc biases. These etch rates are approximately an order of magnitude faster than for CH4/H2/Ar mixtures under the same conditions and there is no polymer deposition on the mask or within the reactor chamber with HI/H2/Ar. Auger Electron Spectroscopy reveals residue-free, stoichiometric surfaces after dry etching in this mixture. As i result, photoluminescence intensities from dry etched samples remain high with little apparent damage introduction. Changes in the near-surface carrier concentration due to hydrogen passivation effects are also negligible with HI-based mixtures in comparison to CH4-based dry etching.

scholarly journals ICP Dry Etching of III-V Nitrides

1997 ◽  
Vol 468 ◽  
Author(s):  
C. B. Vartuli ◽  
J. W. Lee ◽  
J. D. MacKenzie ◽  
S. M. Donovan ◽  
C. R. Abernathy ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Inductively Coupled Plasma ◽  
Dry Etching ◽  
Rf Power ◽  
Inductively Coupled Plasma Etching ◽  
Inductively Coupled ◽  
Dc Bias ◽  
Etch Rates ◽  
Icp Dry Etching

ABSTRACTInductively coupled plasma etching of GaN, AlN, InN, InGaN and InAlN was investigated in CH4/H2/Ar plasmas as a function of dc bias, and ICP power. The etch rates were generally quite low, as is common for III-nitrides in CH4 based chemistries. The etch rates increased with increasing dc bias. At low rf power (150W), the etch rates increased with increasing ICP power, while at 350W rf power, a peak was found between 500 and 750 W ICP power. The etched surfaces were found to be smooth, while selectivities of etch were ≤ 6 for InN over GaN, AlN, InGaN and InAlN under all conditions.

High Density Dry Etching of (Ba,Sr)TiO3 and LaNiO3

1999 ◽  
Vol 596 ◽  
Author(s):  
K. P. Lee ◽  
K. B. Jung ◽  
A Srivastava ◽  
D. Kumar ◽  
R. K. Singh ◽  
...  
Keyword(s):  
Thin Films ◽  
Plasma Etching ◽  
Single Layer ◽  
Dry Etching ◽  
High Density ◽  
Pattern Transfer ◽  
Removal Rates ◽  
Etch Rates ◽  
Density Plasma ◽  
Maximum Removal

AbstractHigh density plasma etching of (Ba,Sr)TiO3 (BST) and LaNiO3 (LNO) thin films was performed in two different plasma chemistries, Cl2/Ar and CH4/H2/Ar. While the latter chemistry produced extremely low etch rates (≤ 100 Å-min−1) under all conditions, the Cl2/Ar produced a smooth anisotropic pattern transfer. The etching was still strongly ion-assisted, but maximum removal rates of ∼900 Å min−1 for both materials were achieved with selectivities of ∼16 for BST and ∼7 for LNO over Si. A single layer of thick (∼7 μm) photoresist is an effective mask under these conditions.

Dry and Wet Etch Processes for NiMnSb, LaCaMnO3 and Related Materials

1997 ◽  
Vol 494 ◽  
Author(s):  
J. Hong ◽  
J. J. Wang ◽  
E. S. Lambers ◽  
J. A. Caballero ◽  
J. R. Childress ◽  
...  
Keyword(s):  
Plasma Etching ◽  
Smooth Surface ◽  
Dielectric Materials ◽  
Ion Density ◽  
Ion Energy ◽  
Sensor Devices ◽  
Etch Rates ◽  
Surface Morphologies ◽  
Wet Etch ◽  
Dry Etch

ABSTRACTA variety of plasma etching chemistries were examined for patterning NiMnSb Heusler thin films and associated A12O3 barrier layers. Chemistries based on SF6 and Cl2 were all found to provide faster etch rates than pure Ar sputtering. In all cases the etch rates were strongly dependent on both the ion flux and ion energy. Selectivities of ≥20 for NiMnSb over A12O3 were obtained in SF6-based discharges, while selectivities ≤5 were typical in Cl2 and CH4/H2 plasma chemistries. Wet etch solutions of HF/H2O and HNO3/H2SO4/H2O were found to provide reaction-limited etching of NiMnSb that was either non-selective or selective, respectively, to A12O3. In addition we have developed dry etch processes based on Cl2/Ar at high ion densities for patterning of LaCaMnO3 (and SmCo permanent magnet biasing films) for magnetic sensor devices. Highly anisotropie features are produced in both materials, with smooth surface morphologies. In all cases, SiO2 or other dielectric materials must be used for masking since photoresist does not retain its geometrical integrity upon exposure to the high ion density plasma.

scholarly journals Selective Etching Of Wide Bandgap Nitrides

1997 ◽  
Vol 483 ◽  
Author(s):  
R. J. Shul ◽  
C. G. Willison ◽  
M. M. Bridges ◽  
J. Han ◽  
J. W. Lee ◽  
...  
Keyword(s):  
Group Iii Nitrides ◽  
High Density ◽  
Chamber Pressure ◽  
Rf Power ◽  
Source Power ◽  
Group Iii ◽  
Inductively Coupled ◽  
Patterning Technique ◽  
Etch Rates ◽  
Coupled Plasmas

AbstractHigh-density plasma etching has been an effective patterning technique for the group-III nitrides due to ion fluxes which are 2 to 4 orders of magnitude higher than more conventional reactive ion etch (RIE) systems. GaN etch rates exceeding 0.68 μm/min have been reported in Cl2/H2/Ar inductively coupled plasmas (ICP) at -280 V dc-bias. Under these conditions, the etch mechanism is dominated by ion bombardment energies which can induce damage and minimize etch selectivity. High selectivity etch processes are often necessary for heterostructure devices which are becoming more prominent as growth techniques improve. In this study, we will report high-density ICP etch rates and selectivities for GaN, AIN, and InN as a function of cathode power, ICP-source power, and chamber pressure. GaN:AIN selectivities > 8:1 were observed in a Cl2/Ar plasma at 10 mTorr pressure, 500 W ICP-source power, and 130 W cathode rf-power, while the GaN:InN selectivity was optimized at ∼ 6.5:1 at 5 mTorr, 500 W ICP-source power, and 130 W cathode rf-power.

Characterization of the CH4/H2/Ar high density plasma etching process for HgCdTe

1999 ◽  
Vol 28 (4) ◽  
pp. 347-354 ◽  
Author(s):  
C. R. Eddy ◽  
D. Leonhardt ◽  
V. A. Shamamian ◽  
J. R. Meyer ◽  
C. A. Hoffman ◽  
...  
Keyword(s):  
Plasma Etching ◽  
High Density ◽  
Etching Process ◽  
Plasma Etching Process ◽  
Density Plasma

scholarly journals Etch Processing of III-V Nitrides

1999 ◽  
Vol 4 (S1) ◽  
pp. 902-913 ◽  
Author(s):  
Charles R. Eddy
Keyword(s):  
Plasma Etching ◽  
Microwave Power ◽  
Ohmic Contacts ◽  
High Density ◽  
Etching Process ◽  
Ion Energy ◽  
Plasma Etching Process ◽  
Device Processing ◽  
The Impact ◽  
Density Plasma

As III-V nitride devices advance in technological importance, a fundamental understanding of device processing techniques becomes essential. Recent works have exposed various aspects of etch processes. The most recent advances and the greatest remaining challenges in the etching of GaN, AlN, and InN are reviewed. A more detailed presentation is given with respect to GaN high density plasma etching. In particular, the results of parametric and fundamental studies of GaN etching in a high density plasma are described. The effect of ion energy and mass on surface electronic properties is reported. Experimental results identify preferential sputtering as the leading cause of observed surface non-stoichiometry. This mechanism provides excellent surfaces for ohmic contacts to n-type GaN, but presents a major obstacle for Schottky contacts or ohmic contacts to p-type GaN. Chlorine-based discharges minimize this stoichiometry problem by improving the rate of gallium removal from the surface. In an effort to better understand the high density plasma etching process for GaN, in-situ mass spectrometry is employed to study the chlorine-based high density plasma etching process. Gallium chloride mass peaks were monitored in a highly surface sensitive geometry as a function of microwave power (ion flux), total pressure (neutral flux), and ion energy. Microwave power and pressure dependencies clearly demonstrate the importance of reactive ions in the etching of wide band gap materials. The ion energy dependence demonstrates the importance of adequate ion energy to promote a reasonable etch rate (≥100-150 eV). The benefits of ion-assisted chemical etching are diminished for ion energies in excess of 350 V, placing an upper limit to the useful ion energy range for etching GaN. The impact of these results on device processing will be discussed and future needs identified.

scholarly journals Impact of Inductively Coupled Plasma Etching Conditions on the Formation of Semi-Polar ( 11 2 ¯ 2 ) and Non-Polar ( 11 2 ¯ 0 ) GaN Nanorods

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2562
Author(s):  
Pierre-Marie Coulon ◽  
Peng Feng ◽  
Tao Wang ◽  
Philip A. Shields
Keyword(s):  
Plasma Etching ◽  
Inductively Coupled Plasma ◽  
Defect Density ◽  
Rf Power ◽  
Resonant Cavities ◽  
Inductively Coupled Plasma Etching ◽  
Inductively Coupled ◽  
Icp Etching ◽  
Dc Bias ◽  
The Impact

The formation of gallium nitride (GaN) semi-polar and non-polar nanostructures is of importance for improving light extraction/absorption of optoelectronic devices, creating optical resonant cavities or reducing the defect density. However, very limited studies of nanotexturing via dry etching have been performed, in comparison to wet etching. In this paper, we investigate the formation and morphology of semi-polar (112¯2) and non-polar (112¯0) GaN nanorods using inductively coupled plasma (ICP) etching. The impact of gas chemistry, pressure, temperature, radio-frequency (RF) and ICP power and time are explored. A dominant chemical component is found to have a significant impact on the morphology, being impacted by the polarity of the planes. In contrast, increasing the physical component enables the impact of crystal orientation to be minimized to achieve a circular nanorod profile with inclined sidewalls. These conditions were obtained for a small percentage of chlorine (Cl2) within the Cl2 + argon (Ar) plasma combined with a low pressure. Damage to the crystal was reduced by lowering the direct current (DC) bias through a reduction of the RF power and an increase of the ICP power.

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