Ion Milling and Reactive Ion Etching of III-V Nitrides

1994 ◽  
Vol 339 ◽  
Author(s):  
S. J. Pearton ◽  
C. R. Abernathy ◽  
F. Ren ◽  
J. R. Lothian

ABSTRACTDry patterning of GaN, InN, AlN and InGaN grown by MOMBE on GaP, Al2 O3 or GaAs substrates was performed with 100–500 eV Ar+ ions at beam angles of incidence ranging from 0–75° from the normal, or with ECR discharges of BCl3/Ar, CH4/H2 or Cl2/H2. The mill rates normalized to the Ar+ beam current were typically a factor of 2 lower than for GaAs and InP (i.e. maximum values of 300–500 Å·min-1·mA-1·cm-2 at 400eV Ar+ beam energy and 60° angle with respect to the beam normal). The surface morphology of the ion milled nitrides was smooth even at 500 eV Ar+ energy, with no evidence for preferential sputtering of N as determined by AES. The ECR dry etch rates were fastest with elevated temperature Cl2/H2discharges, although both of the other chemistries investigated provide smooth, anisotropie pattern transfer. Since the ion mill rates are slow for single-crystal nitrides and less than the mill rates of common masking materials (SiO2, SiNx, photoresist) it appears this technique is useful only for shallow-mesa applications, and that dry etching methods involving an additional chemical component or ion implantation isolation are more practical alternatives for device patterning.

1997 ◽  
Vol 483 ◽  
Author(s):  
Hyun Cho ◽  
C. B. Vartuli ◽  
C. R. Abernathy ◽  
S. M. Donovan ◽  
S. J. Pearton ◽  
...  

AbstractCl2-based Inductively Coupled Plamas with low additional dc self-biases(−100V) produce convenient etch rates(500–1500Å.min−1) for GaN, AIN, InN, InAiN and InGaN. A systematic study of the effects of additive gas(Ar, N2, H2), discharge composition and ICP source power and chuck power on etch rate and surface morphology has been performed. The general trends are to go through a maximum in etch rate with percent C12 in the discharge for all three mixtures, and to have an increase(decrease) in etch rate with source power(pressure). Since the etching is strongly ion-assisted, anisotropic pattern transfer is readily achieved. Maximum etch selectivities of approximately 6 for InN over the other nitrides were obtained.


Author(s):  
P.G. Pawar ◽  
P. Duhamel ◽  
G.W. Monk

A beam of ions of mass greater than a few atomic mass units and with sufficient energy can remove atoms from the surface of a solid material at a useful rate. A system used to achieve this purpose under controlled atmospheres is called an ion miliing machine. An ion milling apparatus presently available as IMMI-III with a IMMIAC was used in this investigation. Unless otherwise stated, all the micro milling operations were done with Ar+ at 6kv using a beam current of 100 μA for each of the two guns, with a specimen tilt of 15° from the horizontal plane.It is fairly well established that ion bombardment of the surface of homogeneous materials can produce surface topography which resembles geological erosional features.


Author(s):  
J. Bentley ◽  
E. A. Kenik

Common artifacts on analytical electron microscope (AEM) specimens prepared from bulk materials are surface films with altered structure and composition that result from electropolishing, oxidation, hydrocarbon contamination, or ion milling (preferential sputtering or deposition of sputtered specimen or support material). Of course, the best solution for surface films is to avoid them by improved specimen preparation and handling procedures or to remove them by low energy ion sputter cleaning, a capability that already exists on some specialized AEMs and one that is likely to become increasingly common. However, the problem remains and it is surprising that surface films have not received more attention with respect to composition determination by energy dispersive X-ray spectrometry (EDS) and electron energy loss spectrometry (EELS).For EDS, an effective first-order correction to remove the contribution of surface films on wedge shaped specimens is to subtract from the spectrum of interest a spectrum obtained under identical conditions (probe current, diffracting conditions, acquisition live time) from a thinner region of the specimen.


1993 ◽  
Vol 63 (1-4) ◽  
pp. 158-162 ◽  
Author(s):  
M. Murtagh ◽  
P.V. Kelly ◽  
P.A.F. Herbert ◽  
M. O'Connor ◽  
G. Duffy ◽  
...  
Keyword(s):  

1998 ◽  
Vol 05 (01) ◽  
pp. 315-320 ◽  
Author(s):  
C. Muggelberg ◽  
M. R. Castell ◽  
G. A. D. Briggs ◽  
D. T. Goddard

The structure of the UO 2+x (111) surface has been investigated by elevated temperature STM. Images of atomic terraces reveal two different types of surface termination. One of them corresponds to the stoichiometric UO 2 (111) surface and can be resolved atomically in empty state images above ~ 1.6 V sample bias. The observed (1 × 1) ordering is thought to be due to uranium states because its occurrence corresponds to the bottom of the empty uranium 5f band. On these terraces mobile oxygen forms a local [Formula: see text] superstructure. The other terrace type observed on top of the UO 2+x (111) surface is thought to be a phase of a higher uranium oxide which has grown epitaxially.


2012 ◽  
Vol 20 (4) ◽  
Author(s):  
I. Izhnin ◽  
A. Izhnin ◽  
H. Savytskyy ◽  
O. Fitsych ◽  
N. Mikhailov ◽  
...  

AbstractThe Hall effect and photoluminescence measurements combined with annealing and/or ion milling were used to study the electrical and optical properties of HgCdTe films grown by molecular-beam epitaxy on GaAs substrates with ZnTe and CdTe buffer layers. Unintentional donor doping, likely from the substrate, which resulted in residual donor concentration of the order of 1015 cm−3, was observed in the films. Also, acceptor states, possibly related to structural defects, were observed.


Author(s):  
Natsuko Asano ◽  
Tamae Omoto ◽  
Jinfeng Lu ◽  
Hirobumi Morita ◽  
Natasha Erdman ◽  
...  

Abstract Understanding solder joints is very important for failure analysis in semiconductor manufacturing because it is commonly used for mounting semiconductor devices on boards. However, regarding sample preparation for analysis, solder poses challenges in crosssection preparation due to the differences in melting point and hardness of its constituents. Therefore, precision cutting methods such as ion milling are required. On the other hand, ion milling method usually causes thermal damage during cutting. In this paper, we tried to optimize the sample temperature during Ar ion milling using liquid nitrogen cooling [1].


Author(s):  
М.С. Воробьёв ◽  
П.В. Москвин ◽  
В.И. Шин ◽  
Н.Н. Коваль ◽  
К.Т. Ашурова ◽  
...  

The paper describes a method for a controlled change in the power of an electron beam during a pulse of submillisecond duration, using a source "SOLO" with a plasma cathode. The beam power is controlled by changing the amplitude of the beam current with a corresponding change in the concentration of the emission plasma. This control method allows generating submillisecond beams of variable power (up to 10 MW at a maximum rate of change of no more than 0.5 MW/µs), which can be used for processing various metallic materials in order to change the functional properties of their surface with the ability to control the rate of input of beam energy into the surface of these materials.


2014 ◽  
Vol 71 (5) ◽  
Author(s):  
Someraa Saleh Shakonah ◽  
Jalil Ali ◽  
Natashah Abd. Rashid ◽  
Kashif Chaudhary

Some of ion beam properties have been investigated by using Lee model code on plasma focus devices which is operated with nitrogen and helium gases. The operation of plasma focus in different pressure regime gives a consistent ion beam properties which can make the plasma focus a reliable ion beam source .These ion beam properties such as ion beam flux, ion beam fluence, ion beam energy, ion beam current, and beam ion number corresponding to gas pressure have been studied for Mather type plasma focus device. The result shows the differences between helium as lighter gas and nitrogen as heavier gas in term of ion beam properties. The fluence and flux are decrease for nitrogen while increase for helium. 


Author(s):  
G. Nowak ◽  
S. Krukowski ◽  
I. Grzegory ◽  
S. Porowski ◽  
Jacek M. Baranowski ◽  
...  

GaN single crystals have been grown from Ga solution. The crystals grow in the form of platelets with their basal plane perpendicular to the c-axis. The two opposite crystal surfaces are not equivalent since one is N- and the other Ga-terminated. Atomic force microscopy has been applied to study surface morphology on both surfaces. It was found that one side is atomically flat. The other side consists of pyramid-like structures about 25 nm in size.The influence of annealing in an NH3+H2 atmosphere in the temperature range from 600°C to 900°C was investigated. Depending on crystal face the results were drastically different. It was found that on the rough side, annealing yields an atomically flat surface with terraces of monolayer height. The size of the terraces depends on the temperature of the annealing. On the originally flat side the surface becomes rougher after annealing. The transformation of surface morphology begins at temperatures below 700°C. Preliminary results of annealing in a hydrogen atmosphere are also reported. These findings are crucial for the understanding and development of GaN homoepitaxy.


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