Effect of N2 Plasma Treatments on Dry Etch Damage in n- and p-type GaN

2000 ◽  
Vol 639 ◽  
Author(s):  
D.G. Kent ◽  
K.P. Lee ◽  
A.P. Zhang ◽  
B. Luo ◽  
M.E. Overberg ◽  
...  

ABSTRACTThe extent of damage recovery by N2 plasma treatment of previously damaged n- and p-GaN has been examined using current-voltage (I-V) characteristics from Schottky diodes. There are two contributions to the observed improvement in the I-V characteristics, namely a simple annealing effect and also a chemical effect from reactive nitrogen. However the N2 plasma treatment does not fully restore the initial electrical properties of the near-surface region.

1985 ◽  
Vol 54 ◽  
Author(s):  
R. T. Tung ◽  
A. F. J. Levi ◽  
J. M. Gibson ◽  
K. K. Ng ◽  
A. Chantre

ABSTRACTThe Schottky barrier heights of single crystal NiSi2 layers on Si(111) have been studied by current-voltage, capacitance-voltage and activation energy techniques. Near ideal behavior is found for Schottky barriers grown on substrates cleaned at ∼820°C in ultrahigh vacuum. The Fermi level positions at the interfaces of single crystal type A and type B NiSi2 are shown to differ by ∼0.14 eV. Transmission electron microscopy demonstrated the epitaxial perfection of these suicide layers. At a cleaning temperature of 1050° C, the near surface region of lightly doped n-type Si was converted to p-type. The presence of a p-n junction was directly revealed by spreading resistance measurements and resulted in a high apparent Schottky barrier height (≥0.75 eV) which no longer bears immediate relationship to the interface Fermi level position.


1991 ◽  
Vol 34 (2) ◽  
pp. 215-216 ◽  
Author(s):  
Vincent W.L. Chin ◽  
John W.V. Storey ◽  
Martin A. Green

1992 ◽  
Vol 262 ◽  
Author(s):  
J. L. Benton

ABSTRACTThe electrical and optical properties of defects introduced by Reactive Ion Etching (RIE) in the near surface region of Si after dry etching with various gases and plasma conditions is studied with spreading Resistance (SR), photoluminescence (PL), and capacitance-voltage profiling (C-V). Plasma etching in chlorine and fluorine based gases produce donors at the surface in both n-type and p-type, Czochralski and float-zone silicon. Isochronal annealing reveals the presence of two distinct regions of dopant compensation. The surface damage region is confined to 1000 Å and survives heat treatment at 400°C, while the defect reaction region extends ≥ 1 μm in depth and recovers by 250°C. A comprehensive picture of the interstitial defect reactions in RIE silicon is completed. The interstitial defects, Ci and Bi, created in the ion damaged near surface region, undergo recombination enhanced diffusion caused by the presence of ultraviolet light in the plasma, resulting in the long range diffusion into the Si bulk. Subsequently, the interstitial atoms are trapped by the background impurities forming the defect pairs, CiOi, CSCi, or BiOi, which are observed experimentally. The depth of the diffusion-limited trapping and the probability of forming specific pairs depends on the relative concentrations of the reactants, oxygen, carbon or boron, present in the bulk material.


2012 ◽  
Vol 1447 ◽  
Author(s):  
Sabina Abdul Hadi ◽  
Pouya Hashemi ◽  
Nicole DiLello ◽  
Ammar Nayfeh ◽  
Judy L. Hoyt

ABSTRACTIn this paper the effect of Si1-xGex absorber layer thickness on thin film a-Si:H/crystalline-Si1-xGex/c-Si heterojunction solar cells (HIT cells) is studied by simulation and experiment. Cells with 1, 2 and 4 μm-thick epitaxial cap layers of p-type Si0.59Ge0.41 on top of 5 μm Si1-xGex graded buffer layers are fabricated and compared to study the effect of the absorber layer thickness. The results show no change in Voc (0.41V) and that Jsc increases from 17.2 to 18.1 mA/cm2 when the Si0.59Ge0.41 absorber layer thickness is increased from 1 to 4 μm. The effect of thickness on Jsc is also observed for 2 and 4 μm-thick Si and Si0.75Ge0.25 absorber layers. Experiments and simulations show that larger Ge fractions result in a higher magnitude and smaller thickness dependence of Jsc, due to the larger absorption coefficient that increases optical carrier generation in the near surface region for larger Ge contents.


1999 ◽  
Vol 572 ◽  
Author(s):  
Q. Zhang ◽  
V. Madangarli ◽  
S. Soloviev ◽  
T. S. Sudarshan

ABSTRACTP-type 6H SiC Schottky barrier diodes with good rectifying characteristics upto breakdown voltage as high as 1000V have been successfully fabricated using metal-overlap over a thick oxide layer (∼ 6000 Å) as edge termination and Al as the barrier metal. The influence of the oxide layer edge termination in improving the reverse breakdown voltage as well as the forward current – voltage characteristics is presented. The terminated Schottky diodes indicate a factor of two higher breakdown voltage and 2–3 times larger forward current densities than those without edge termination. The specific series resistance of the unterminated diodes was ∼228 mΩ-cm2, while that of the terminated diodes was ∼84 mΩ-cm2.


Author(s):  
Н.М. Богатов ◽  
Л.Р. Григорьян ◽  
А.И. Коваленко ◽  
М.С. Коваленко ◽  
Ф.А. Колоколов ◽  
...  

Irradiation with low-energy protons leads to a change in the electrophysical, optical, and other properties of the surface region of semiconductor structures, which creates additional possibilities for modifying semiconductor devices. The work is devoted to the study of the effect of radiation defects created by low-energy protons at a sample temperature of 83 K on the properties of two-sided silicon photovoltaic structures with a diffusion n^+-p junction. Samples of n^+-p-p^+ type were irradiated with a flux of protons with an energy of 40 keV or 180 keV and a dose of 1015 cm^-2. To explain the observed regularities in the variation of the parameters of the current-voltage characteristics and the transmission coefficients, the distribution of the average number of interstitial silicon, vacancies, divacancies, and disordering regions created under these conditions on the unit projective path length by one proton in the diffusion layer and the space charge region of the n^+-p junction was calculated. It is shown that protons with an initial energy of 40 keV predominantly change the physical properties of a layer with a high concentration of donors, and protons with an initial energy of 180 keV are properties of the space-charge region in a layer containing acceptors. The number of radiation defects in the maximum spatial distribution in the n-region is much smaller than in the p-region.


Author(s):  
Д.А. Кудряшов ◽  
А.С. Гудовских ◽  
А.А. Максимова ◽  
А.И. Баранов ◽  
А.В. Уваров ◽  
...  

The possibility of evaluation the degree of damage to the near-surface layer of p-type silicon using a selective contact based on MoOx/p-Si is shown. A strong sensitivity of the current-voltage characteristics to the states on the silicon surface formed during the deposition of silicon oxide by magnetron sputtering is demonstrated.


1999 ◽  
Vol 588 ◽  
Author(s):  
V. Higgs

AbstractA new Photoluminescence (PL) method has been developed to detect defects in the near surface region of Si wafers and Si-on-insulator (SOI) structures. Wafer maps (up to 300 min diameter) can be readily acquired and areas of interest can be scanned at high resolution (≈1 μm). The excitation laser beam is modulated to confine the photogenerated carriers; defects are observed due to the localised reduction of the carrier lifetime. Si p-type (10 Ohm.cm) wafers were intentionally contaminated with various levels of Ni and Fe (1×109−5×1010 atoms/cm2) and annealed. The PL intensity was observed to decrease due to the metal related non-radiative defects. Whereas in contrast, for Cu, (1×109−5×1010 atoms/cm2) the PL intensity actually increased initially and reached a maximum value at 5×109 atoms/cm2. It is suggested that during contamination the Cu related defects have complexed with existing defects (that have stronger recombination properties) and increased the PL. Further Cu contamination (1×1010−5×1010 atoms/cm2) produced a reduction in the PL intensity. PL mapping of strained SiGe epilayers showed that misfit dislocations can be detected and PL can be used to evaluate material quality.PL maps of SOI bonded wafers revealed that the non-bonded areas, voids or gas bubbles could be detected. This was confirmed using defect etching and polishing, voids as small as ≈30 μm in diameter could be detected. SOI wafers fabricated using the separation by implanted oxygen (SIMOX) technique were also analysed, variations in the recombination properties of the layer could be observed. Further inspection using transmission electron microscopy (TEM) revealed that the defects were non-uniformities of the buried oxide covering several microns and containing tetrahedral stacking faults. Focused ion beam (FIB) milling and secondary ion mass spectrometry (SIMS) showed that these defects were at the Si/SiO2 interface and were chemically different to the surrounding area.


1995 ◽  
Vol 395 ◽  
Author(s):  
J.T. Trexler ◽  
S.J. Miller ◽  
P.H. Holloway ◽  
M.A. Khan

ABSTRACTThe reactions between Au, Au/Ni and Au/C/Ni thin films on p-GaN have been studied using current-voltage (I-V) measurements, Auger electron spectroscopy (AES) and secondary ion mass spectrometry (SIMS). The metallization schemes consisted of ≈2000Ǻ sputtered Au, 1000Ǻ Au/500Ǻ Ni, and 1000Ǻ Au/100Ǻ C/500Ǻ Ni electron beam evaporated. The Au/Ni metallization scheme is of particular interest since it is the basis for the most commonly used ohmic p-type contacts for blue GaN LED’s. Au does not decompose the GaN matrix, while Ni has been shown to react with GaN above a temperature of 400° C for times longer than 5 minutes. Upon decomposition of the GaN by Ni, incorporation of C at the metal/GaN interface occurred. It is believed that a regrowth of GaN occurred, with the surface region being doped with C. Attempts at increasing this doping concentration by introducing an interfacial C layer were not successful.


2001 ◽  
Vol 30 (3) ◽  
pp. 196-201 ◽  
Author(s):  
Q. Zhang ◽  
V. Madangarli ◽  
M. Tarplee ◽  
T. S. Sudarshan

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