Pt/Au and W/Pt/Au Schottky Contacts to Bulk n-ZnO.

2004 ◽  
Vol 829 ◽  
Author(s):  
Kelly Ip ◽  
Brent Gila ◽  
Andrea Onstine ◽  
Eric Lambers ◽  
Young-Woo Heo ◽  
...  
Keyword(s):  
Schottky Barrier ◽  
Schottky Barrier Height ◽  
Schottky Contacts ◽  
Ozone Exposure ◽  
Saturation Current ◽  
Post Deposition Annealing ◽  
Barrier Heights ◽  
Saturation Current Density ◽  
Uv Ozone ◽  
Post Deposition

ABSTRACTUV-ozone cleaning prior to metal deposition of either e-beam Pt contacts or sputtered W contacts on n-type single-crystal ZnO is found to significantly improve their rectifying characteristics. Pt contacts deposited directly on the as-received ZnO surface are Ohmic but show rectifying behavior with ozone cleaning. The Schottky barrier height of these Pt contacts was 0.70 eV, with ideality factor of 1.5 and a saturation current density of 6.2 × 10−6 A·cm−2. In contrast, the as-deposited W contacts are Ohmic, independent of the use of ozone cleaning. Post-deposition annealing at 700 °C produces rectifying behavior with Schottky barrier heights of 0.45 eV for control samples and 0.49 eV for those cleaned with ozone exposure. The improvement in rectifying properties of both the Pt contacts is related to removal of surface carbon contamination from the ZnO.

Schottky contacts to GaxIn1−xP barrier enhancement layers on InP and InGaAs

1996 ◽  
Vol 74 (S1) ◽  
pp. 104-107
Author(s):  
Z. Pang ◽  
P. Mascher ◽  
J. G. Simmons ◽  
D. A. Thompson
Keyword(s):  
Molecular Beam Epitaxy ◽  
Band Gap ◽  
Schottky Barrier ◽  
Molecular Beam ◽  
Schottky Barrier Height ◽  
Schottky Contacts ◽  
Barrier Heights ◽  
Gas Source ◽  
Layer Increase ◽  
Electrode Metal

In our investigations, Au, Al, Ni, Pt, Ti, and combinations thereof were deposited on InP and InGaAs by e-beam evaporation to form Schottky contacts. The Schottky-barrier heights of these diodes determined by forward I–V and (or) reverse C–V measurements lie between 0.38–0.48 eV. To increase the Schottky-barrier height, a strained GaxIn1−xP layer was inserted between the electrode metal(s) and the semiconductor. This material, which has a band-gap larger than InP, was grown by gas-source molecular beam epitaxy. The Schottky-barrier heights, which generally depend on the gallium fraction, x, and the thickness of the strained GaxIn1−xP layer, increase and are in the range of 0.56–0.65 eV in different contact schemes.

Schottky Barrier Heights of A1/p-Sil-xGex

1995 ◽  
Vol 379 ◽  
Author(s):  
R. L. Jiang ◽  
J. Li ◽  
X. C. Zhou ◽  
J. N. Liu ◽  
Y. D. Zheng
Keyword(s):  
Schottky Barrier ◽  
Schottky Barrier Height ◽  
Strain Relaxation ◽  
Chemical Vapor ◽  
Schottky Contacts ◽  
Rapid Thermal Process ◽  
Strained Si ◽  
Strained Layers ◽  
Barrier Heights ◽  
Pressure Chemical

ABSTRACTElectrical properties of Al/p-Sil-xGex Schottky contacts were investigated. The Sil-xGexstrained layers were grown by using Rapid Thermal Process/Very Low Pressure-Chemical Vapor Deposition. It was found that Schottky barrier height decreased with increasing Ge fraction. The decrement is in accordance with the decrement of the bandgap of the strained Sil-xGex. The Fermi level at the interface is pinned at about 0. 43eV below the conduction band. The influence of strain relaxation for SiGe alloy layers and the Si cap layers on the properties of Schottky contacts were also investigated.

Impact of Interface Traps on Current-Voltage Characteristics of 4H-SiC Schottky-Barrier Diodes

2014 ◽  
Vol 778-780 ◽  
pp. 710-713 ◽  
Author(s):  
Hamid Amini Moghadam ◽  
Sima Dimitrijev ◽  
Ji Sheng Han
Keyword(s):  
Schottky Barrier ◽  
Schottky Barrier Height ◽  
Schottky Diodes ◽  
Forward Bias ◽  
Interface Traps ◽  
Barrier Heights ◽  
Current Voltage ◽  
Donor Type ◽  
Current Voltage Characteristics ◽  
Expected Values

This paper presents a physical model based on interface traps to explain both the larger barrier heights of practical Schottky diodes in comparison to the theoretically expected values and the appearance of a knee in the log I–V characteristics. According to this model, acceptor-type interface traps near the valance band increase the Schottky barrier height, which shifts the log I–V characteristic to higher forward-bias voltages. In addition to the acceptor traps, donor-type interface traps can appear near the conduction band, and when they do, they cause the knee in the log I–V characteristics as their energy level falls below the Fermi level and the charge associated with these traps changes from positive to neutral.

Analysis of temperature-dependent Schottky barrier parameters of Cu–Au Schottky contacts to n-InP

2012 ◽  
Vol 90 (1) ◽  
pp. 73-81 ◽  
Author(s):  
V. Lakshmi Devi ◽  
I. Jyothi ◽  
V. Rajagopal Reddy
Keyword(s):  
Schottky Barrier ◽  
Barrier Height ◽  
Gaussian Distribution ◽  
Ideality Factor ◽  
Thermionic Emission ◽  
Schottky Contacts ◽  
Temperature Dependent ◽  
Semiconductor Interface ◽  
Zero Bias ◽  
Barrier Heights

In this work, we have investigated the electrical characteristics of Au–Cu–n-InP Schottky contacts by current–voltage (I–V) and capacitance–voltage (C–V) measurements in the temperature range 260–420 K in steps of 20 K. The diode parameters, such as the ideality factor, n, and zero-bias barrier height, Φb0, have been found to be strongly temperature dependent. It has been found that the zero-bias barrier height, Φb0(I–V), increases and the ideality factor, n, decreases with an increase in temperature. The forward I–V characteristics are analyzed on the basis of standard thermionic emission (TE) theory and the assumption of gaussian distribution of barrier heights, due to barrier inhomogeneities that prevail at the metal–semiconductor interface. The zero-bias barrier height Φb0 versus 1/2kT plot has been drawn to obtain the evidence of a gaussian distribution of the barrier heights. The corresponding values are Φb0 = 1.16 eV and σ0 = 159 meV for the mean barrier height and standard deviation, respectively. The modified Richardson plot has given mean barrier height, Φb0, and Richardson constant, A**, as 1.15 eV and 7.34 Acm−2K−2, respectively, which is close to the theoretical value of 9.4 Acm−2K−2. Barrier heights obtained from C–V measurements are higher than those obtained from I–V measurements. This inconsistency between Schottky barrier heights (SBHs) obtained from I–V and C–V measurements was also interpreted. The temperature dependence of the I–V characteristics of the Au–Cu–n-InP Schottky diode has been explained on the basis of TE mechanism with gaussian distribution of the SBHs.

Internal Photoemission Measurements for the Determination of Schottky Barrier Height on a-Si, Ge:H, F Alloys

1986 ◽  
Vol 70 ◽  
Author(s):  
V. Chu ◽  
S. Aljishi ◽  
D. Slobodin ◽  
S. Wagner
Keyword(s):  
Glow Discharge ◽  
Schottky Barrier ◽  
Entire Range ◽  
Schottky Barrier Height ◽  
Alloy Composition ◽  
Similar Increase ◽  
Internal Photoemission ◽  
Barrier Heights ◽  
Optical Gap

ABSTRACTWe report measurements of internal photoemission from Ni, Au, and Pd contacts into a-Si, Ge:H, F alloys. The alloys were prepared by d.c. glow discharge decomposition of either SiF4 or SiH4 and GeF4, and H2. The sharp exponential drop in subgap absorption in these alloys, measured by the Constant Photocurrent Method (CPM), allows the determination of barrier heights using internal photoemission thresholds. The barrier heights of Ni, Au and Pd contacts are presented as a function of alloy composition. We find Ni has the lowest barrier heights while Au shows the highest barrier heights over the entire range of Eopt. We also find that for the Ni and Au contacts, ΦB varies as 1/2 the optical gap. In the case of Pd, ΦB shows a dependence of 1/3 the optical gap. We observed an increase in ΦB for Pd contacts when etched with a diluted HF solution prior to metallization. A similar increase in ΦD was not observed for the Au and Ni contacts.

Defect Reduction in Si-based Metal-Semiconductor-Metal Photodetectors with Cryogenic Processed Schottky Contacts

2005 ◽  
Vol 864 ◽  
Author(s):  
M. Li ◽  
W. A. Anderson
Keyword(s):  
Schottky Barrier ◽  
Barrier Height ◽  
Dark Current ◽  
Schottky Barrier Height ◽  
Schottky Diodes ◽  
Schottky Contacts ◽  
Metal Deposition ◽  
Active Area ◽  
Electrode Spacing ◽  
Metal Semiconductor Metal

AbstractMetal-Semiconductor-Metal photodetectors (MSM-PD's) and simple Schottky diodes were fabricated using a low temperature (LT) technique to greatly reduce the device dark current. LT processing for metal deposition increased Schottky barrier height by improving the interface between metal and semiconductor to reduce the leakage current of the device. The structure consists of a 20 Å oxide over the active area to passivate surface states, a thicker oxide under contact pads to reduce dark current and the interdigitated Schottky contacts. A comparison was made for Schottky metal deposited with the substrate at 25 °C or -50 °C (LT). The devices fabricated using the LT process had better I-V characteristics compared to detectors fabricated using the standard room temperature (RT) metal deposition technique. The dark current for the LT film was found to be one to three orders lower in magnitude compared to the film deposited at RT. In one case, for example, the dark current was significantly reduced from 1.69 nA to 4.58 pA at 1.0 V. The active area for the device was determined to be 36 × 50 μm2 with 4 μm electrode width and 4 μm electrode spacing. Additionally, LT-MSM-PD's exhibited an excellent linear relationship between the photo-current and the incident light power. The Schottky barrier height for LT processing was found to be 0.79 eV; however, this value was 0.1 eV more than that of the same contact obtained by RT processing.

Delineation of Defects Reducing Schottky Barrier Heights on 4H-SiC by the Electrochemical Deposition

2008 ◽  
Vol 600-603 ◽  
pp. 373-376
Author(s):  
Masashi Kato ◽  
Kazuya Ogawa ◽  
Masaya Ichimura
Keyword(s):  
Schottky Barrier ◽  
Barrier Height ◽  
Electrochemical Deposition ◽  
Schottky Barrier Height ◽  
Proper Time ◽  
Etch Pits ◽  
Barrier Heights ◽  
Etch Pit ◽  
Deposition Voltage ◽  
Deposited Films

We identified regions with low Schottky barrier height on 4H-SiC surfaces by the electrochemical deposition of ZnO. When we adopt an appropriate deposition voltage, ZnO grew preferentially at the regions with the low Schottky barrier height. Thus, we were able to identify the ZnO film only at these regions if we stopped the deposition at a proper time. We compared positions of the deposited film and etch pit after molten NaOH etching. As a result, in a bulk 4H-SiC, the films were deposited around some of micropipe positions. On the other hand, in an epitaxial 4H-SiC layer, although approximately a half of deposited films seemed to grow at the etch-pit defect positions, other deposited films were grown at positions without etch-pit defects. Therefore the Schottky barrier heights were reduced by not only defects emerging as etch pits but also other kind of origins in epitaxial 4H-SiC.

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