Current Transport in Cryogenic Processed Metal/InP and GaAs Interfaces

1994 ◽  
Vol 337 ◽  
Author(s):  
L. He ◽  
Z.Q. Shi ◽  
W.A. Anderson
Keyword(s):  
Barrier Height ◽  
Room Temperature ◽  
Conduction Mechanism ◽  
Forward Bias ◽  
Thermionic Emission ◽  
Testing Temperature ◽  
Current Transport ◽  
Saturation Current Density ◽  
Thermionic Field Emission ◽  
Lt Inp

ABSTRACTSchottky contacts to n type InP and GaAs have been made by deposition on substrates cooled to low temperature (LT=77K) in a vacuum close to 10-7 Torr.The Schottky barrier height, ФB, was found to be as high as 0.96eV with Pd/InP and 0.95eV for Au/GaAs. This indicated a significant increase in ФB compared with the room temperature (RT=300K) deposition. For diodes fabricated at room temperature, the reverse saturation current density, JO, decreased sharply with decrease in measuring temperature. For the RT InP diodes, the conduction mechanism was controlled by thermionic emission (TE). For the LT InP diodes, the value of JO was about six orders smaller than for the RT diode at the same temperature. As testing temperature decreased, the barrier height was increased from 0.96 to 1.15eV, with a temperature coefficient of -3.2 x 10-4 eV/K. The forward transport mechanism was controlled by thermionic field emission (TFE). For the GaAs diodes, thermionic emission (TE) dominated in the current transport at room temperature for both RT and LT diodes. At low testing temperature, RT diodes exhibited an excess current component at low forward bias.

Current Transport Study of Schottky and P-N Junction Solar Cells Using Metal-Induced Growth Poly-Si Thin Films

2004 ◽  
Vol 836 ◽  
Author(s):  
Chunhai Ji ◽  
Joon-Dong Kim ◽  
Wayne A. Anderson
Keyword(s):  
Barrier Height ◽  
Field Emission ◽  
Ideality Factor ◽  
Carrier Density ◽  
Transport Mechanism ◽  
Thermionic Emission ◽  
Current Transport ◽  
Oxygen Level ◽  
Thermionic Field Emission ◽  
One Step

AbstractPoly-Si thin films deposited at low temperature by using the metal-induced growth (MIG) method have the advantage of less metal impurity contaminations and relative large grains with preferred crystal orientation of (220). In recent research, the Schottky solar diode made of MIG poly-Si shows Jsc of 12 mA/cm2 and Voc of 0.214V. In this paper, current transport mechanisms were studied by current-voltage-temperature (I-V-T) testing from 100 K to 400K. For the samples deposited by a one-step sputtering process, the large value of ideality factor (n) and abnormal increase of barrier height with the temperature implies that the current transport mechanism does not follow the pure thermionic-emission theory, which was proven to be thermionic-field emission due to the highly doped Si film. By using a two-step sputtering process, the ideality factor and Au-Schottky barrier height at room temperature were about 1.5 and 0.7 eV, which was improved from one-step sputtering. Hydrogenation by electron cyclotron resonance (ECR) plasma can further improve the Schottky diode ideality factor and barrier height. Although a low-level Phosphors-doped Si target was used for poly-Si thin film deposition, a thermionic-field emission mechanism was still found by plotting the activation energy (E0) versus the testing temperature range. Capacitance-voltage (C-V) analysis revealed an unexpected carrier density of 1017 cm−3 level, which is 1000 times higher than the doping density level in the Si film. “Oxygen thermal donor” effect was assumed due to high oxygen level (1020 cm−3) detected by SIMS and processing at ∼ 600 °C. Increasing of the total carrier density due to the oxygen donor may cause the transport mechanism change from pure thermionic emission to thermionic-field emission. Reducing oxygen in the Si film by filtering the sputtering gas to 50 ppb oxygen level was proven to be effective. C-V results gave ∼1016 cm−3 level of carrier density after using oxygen filtering. P-N junction solar cells were made by B-ion implantation into n-type Si film and dopant activation at 700 °C. I-V-T study showed similar curves for P-N junction as for Schottky junction devices. This implies that the current transport was dominated by the Si films instead of the junctions for both Schottky and P-N junction devices.

Current Transport in W and WSIX Ohmic Contacts to Ingan and Inn

1997 ◽  
Vol 468 ◽  
Author(s):  
C. B. Vartuli ◽  
S. J. Pearton ◽  
C. R. Abernathy ◽  
J. D. MacKenzie ◽  
M. L. Lovejoy ◽  
...  
Keyword(s):  
Room Temperature ◽  
Ohmic Contacts ◽  
Conduction Mechanism ◽  
Specific Resistance ◽  
Thermionic Emission ◽  
Contact Structures ◽  
Specific Contact Resistance ◽  
Current Transport ◽  
Deposited Metal ◽  
Specific Contact

ABSTRACTThe temperature dependence of the specific contact resistance of W and WSi0.44 contacts on n+ In0.55Ga0.35N and InN was measured in the range -50 °C to 125 °C. The results were compared to theoretical values for different conduction mechanisms, to further elucidate the conduction mechanism in these contact structures. The data indicates the conduction mechanism is field emission for these contact schemes for all but as-deposited metal to InN where thermionic emission appears to be the dominant mechanism. The contacts were found to produce low specific resistance ohmic contacts to InGaN at room temperature, ϱc ∼ 10-7 Ω ·cm2 for W and ϱc of 4× 10-7 Ω ·cm for WSix. InN metallized with W produced ohmic contacts with ϱc ∼ 10-6 Ω ·cm and ϱc ∼ 10-6 Ω ·cm. for WSix at room temperature.

Characterization of Metal/Si1-xGex/Si Diodes Fabricated by Cryogenic Processing

1995 ◽  
Vol 379 ◽  
Author(s):  
L. He ◽  
E. Li ◽  
Z.Q. Shi ◽  
R.L. Jiang ◽  
J. L. Liu ◽  
...  
Keyword(s):  
Barrier Height ◽  
Room Temperature ◽  
Conduction Mechanism ◽  
Schottky Diodes ◽  
Thermionic Emission ◽  
Nitrogen Atmosphere ◽  
Thin Layers ◽  
Electrical Characteristics ◽  
Current Voltage ◽  
Cryogenic Processing

ABSTRACTSchottky diodes were fabricated by evaporating metal thin layers on p-Si1-xGex by cryogenic processing. The cryogenic processing, with substrate temperature cooled to as low as 77K (LT), has been successfully used to enhance metal/III-V semiconductor Schottky barrier height[1]. The electrical characteristics of the diodes were investigated by current-voltage (IV) and current-temperature (I-T) measurements. In order to study the effect of silicide formation on diode characteristics, furnace annealing was performed in nitrogen atmosphere at 450°C and 550°C, respectively. Two kinds of samples with gemanium composition x of 0.17 and 0.20 were used. The electrical characteristics showed the barrier height фB decreased with the increase of the gemanium composition. The annealing temperatures up till to 550°C did not affect the I-V characteristics at room temperature, however, the conduction mechanism showed obvious difference comparing to the as-deposited diodes by I-V-T analysis. For Pd as Schottky metal, very similar results were obtained for the LT as-deposited diodes and the ordinary room temperature (RT) deposited diodes after 550° annealing, they both showed thermionic emission dominated conduction mechanism.

Current Transport Mechanisms in Au-Free Metallizations for CMOS Compatible GaN HEMT Technology

2020 ◽  
Vol 1004 ◽  
pp. 725-730
Author(s):  
Fabrizio Roccaforte ◽  
Monia Spera ◽  
Salvatore Di Franco ◽  
Raffaella Lo Nigro ◽  
Patrick Fiorenza ◽  
...  
Keyword(s):  
Barrier Height ◽  
Ohmic Contacts ◽  
Specific Contact Resistance ◽  
Current Transport ◽  
Large Area ◽  
Si Substrates ◽  
Ohmic Behavior ◽  
Specific Contact ◽  
Thermionic Field Emission

Gallium nitride (GaN) and its AlGaN/GaN heterostructures grown on large area Si substrates are promising systems to fabricate power devices inside the existing Si CMOS lines. For this purpose, however, Au-free metallizations are required to avoid cross contaminations. In this paper, the mechanisms of current transport in Au-free metallization on AlGaN/GaN heterostructures are studied, with a focus on non-recessed Ti/Al/Ti Ohmic contacts. In particular, an Ohmic behavior of Ti/Al/Ti stacks was observed after an annealing at moderate temperature (600°C). The values of the specific contact resistance ρc decreased from 1.6×104 Ω.cm2 to 7×105 Ω.cm2 with increasing the annealing time from 60 to 180s. The temperature dependence of ρc indicated that the current flow is ruled by a thermionic field emission (TFE) mechanism, with barrier height values of 0.58 eV and 0.52 eV, respectively. Finally, preliminary results on the forward and reverse bias characterization of Au-free tungsten carbide (WC) Schottky contacts are presented. This contact exhibited a barrier height value of 0.82 eV.

Current-transport mechanism in Au/V-doped PVC+TCNQ/p-Si structures

2015 ◽  
Vol 29 (13) ◽  
pp. 1550076 ◽  
Author(s):  
H. Tecimer ◽  
Ö. Vural ◽  
A. Kaya ◽  
Ş. Altındal
Keyword(s):  
Temperature Coefficient ◽  
Transport Mechanism ◽  
Forward Bias ◽  
Thermionic Emission ◽  
Negative Temperature ◽  
Positive Temperature ◽  
Current Transport ◽  
Insulator Layer ◽  
Zero Bias ◽  
Current Transport Mechanism

The forward and reverse bias current–voltage (I–V) characteristics of Au/V-doped polyvinyl chloride+Tetracyanoquino dimethane/porous silicon (PVC+TCNQ/p-Si) structures have been investigated in the temperature range of 160–340 K. The zero bias or apparent barrier height (BH) (Φ ap = Φ Bo ) and ideality factor (n ap = n) were found strongly temperature dependent and the value of n ap decreases, while the Φ ap increases with the increasing temperature. Also, the Φ ap versus T plot shows almost a straight line which has positive temperature coefficient and it is not in agreement with the negative temperature coefficient of ideal diode or forbidden bandgap of Si (α Si = -4.73×10-4 eV/K ). The high value of n cannot be explained only with respect to interfacial insulator layer and interface traps. In order to explain such behavior of Φ ap and n ap with temperature, Φ ap Versus q/2kT plot was drawn and the mean value of (Φ Bo ) and standard deviation (σs) values found from the slope and intercept of this plot as 1.176 eV and 0.152 V, respectively. Thus, the modified ( ln (Io/T2)-(qσs)2/2(kT)2 versus (q/kT) plot gives the Φ Bo and effective Richardson constant A* as 1.115 eV and 31.94 A ⋅(cm⋅K)-2, respectively. This value of A*( = 31.94 A⋅( cm ⋅K)-2) is very close to the theoretical value of 32 A ⋅(cm⋅K)-2 for p-Si. Therefore, the forward bias I–V–T characteristics confirmed that the current-transport mechanism (CTM) in Au/V-doped PVC+TCNQ/p-Si structures can be successfully explained in terms of the thermionic emission (TE) mechanism with a Gaussian distribution (GD) of BHs at around mean BH.

AN ASSESSMENT ON ELECTRICAL CHARACTERIZATION OF Ni/n-Si SCHOTTKY RECTIFIERS WITH AND WITHOUT Ta2O5 INTERFACIAL OXIDE LAYER

2019 ◽  
Vol 26 (10) ◽  
pp. 1950073 ◽  
Author(s):  
N. NANDA KUMAR REDDY ◽  
P. ANANDA ◽  
V. K. VERMA ◽  
K. RAHIM BAKASH
Keyword(s):  
Schottky Barrier ◽  
Oxide Layer ◽  
Barrier Height ◽  
Series Resistance ◽  
Schottky Diodes ◽  
Forward Bias ◽  
Thermionic Emission ◽  
Mis Structure ◽  
Schottky Barrier Diodes ◽  
Mis Structures

We have fabricated Ni/[Formula: see text]-Si metal–semiconductor (MS) and Ni/Ta2O5/[Formula: see text]-Si metal-insulator–semiconductor (MIS) Schottky barrier diodes at room temperature and studied their current density–voltage (J–V) and capacitance–voltage (C–V) characteristic properties. The forward bias J–V characteristics of the fabricated MS and MIS devices have been evaluated with the help of the thermionic emission (TE) mechanism. Schottky barrier height (SBH) values of 0.73 and 0.84[Formula: see text]eV and ideality factor values of 1.75 and 1.46 are extracted using J–V measurements for MS and MIS Schottky barrier diodes without and with Ta2O5 interfacial oxide layer, respectively. It was noted that the incorporation of Ta2O5 interfacial oxide layer enhanced the value of SBH for the MIS device because this oxide layer produced the substantial barrier between Ni and [Formula: see text]-Si and this obtained barrier height value is better than the conventional metal/[Formula: see text]-Si (MS) Schottky diodes. The rectification ratio (RR) calculated at [Formula: see text][Formula: see text]V for the MS structure is found to be [Formula: see text] and the MIS structure is found to be [Formula: see text]. Using Chung’s method, the series resistance ([Formula: see text]) values are calculated using [Formula: see text]/[Formula: see text] vs I plot and are found to be 21,603[Formula: see text][Formula: see text] for the Ni/[Formula: see text]-Si (MS) and 5489[Formula: see text][Formula: see text] for the Ni/Ta2O5/[Formula: see text]-Si (MIS) structures, respectively. In addition, [Formula: see text] vs [Formula: see text] plot has been utilized to evaluate the series resistance ([Formula: see text]) values and are found to be 14,064[Formula: see text][Formula: see text] for the Ni/[Formula: see text]-Si (MS) and 2236[Formula: see text][Formula: see text] for the Ni/Ta2O5/[Formula: see text]-Si (MIS) structures, respectively. In conclusion, by analyzing the experimental results, it is confirmed that the good quality performance is observed in Ni/Ta2O5/[Formula: see text]-Si (MIS) type SBD when compared to Ni/[Formula: see text]-Si (MS) type SBD and can be accredited to the intentionally formed thin Ta2O5 interfacial oxide layer between Nickel and [Formula: see text]-type Si.

Laterally Inhomogeneous Barrier Height Analysis for Thermally Annealed CuNiTi/p-InP Contacts

2017 ◽  
Vol 890 ◽  
pp. 127-130
Author(s):  
Bahattin Abay
Keyword(s):  
Barrier Height ◽  
Thermal Annealing ◽  
Ideality Factor ◽  
Forward Bias ◽  
Thermionic Emission ◽  
Characteristic Parameters ◽  
Inp Substrate ◽  
Current Voltage ◽  
Positively Charged ◽  
Device Technology

The fabrication of thermally stable Schottky contacts with high barrier height (BH) to InP is one of the main challenges for InP-based device technology. CuNiTi/p-InP Schottky barrier diodes (SBDs) (25 dots) on p-InP substrate were fabricated by conventional vacuum deposition. Characteristic parameters such as BH and ideality factor (n) of as-deposited and annealed CuNiTi/p-InP diodes have been computed by thermionic emission (TE) theory from the forward-bias current-voltage (I-V) data, at room temperature and in dark. The value of BH and n varies from 0.452 to 0.631 eV and 1.172 to 2.815, respectively for the as-deposited SBDs. The results showed that characteristic parameters of CuNiTi/p-InP structures differ from one device to another even though they were identically prepared. Hence, to overcome these problems post thermal annealing was implemented since the annealing process can improve the interfacial quality as well as can induce a recrystallization of the gate metals. BH values for CuNiTi/p-InP SBDs have also varied from 0.765 to 0.804 eV, and ideality factor n from 1.161 to 1.253 after annealing at 500 °C for two minutes. As a result of the thermal annealing, it has been seen that the BH values of the annealed SBDs are larger than those of the as-deposited ones. A statistical study on the diode parameters has been made. The experimental BH and ideality factor distributions were fitted by a Gaussian distribution (GD) function. Lateral homogeneous BH (φhom.) values of 0.628 eV and 0.886 eV for the as-deposited and annealed CuNiTi/p-InP SBDs has been obtained from the φeff.-n plots by using Tung’s lateral inhomogeneity approach. An increment of 0.258 eV in the BH for the 500 °C annealing devices with respect to that of the as-deposited ones has been ascribed to the formation of the positively charged interface defects that electrically actives in the metal-semiconductor (MS) interface.

scholarly journals Temperature Dependent Current Transport Mechanism of Photopolymer Based Al/NOA60/p-Si MPS Device

2021 ◽  
Author(s):  
Şadan Özden ◽  
Nejmettin Avcı ◽  
Osman Pakma ◽  
Afşin İshak Kariper
Keyword(s):  
Forward Bias ◽  
Thermionic Emission ◽  
Current Transport ◽  
Temperature Dependent ◽  
Cross Sectional ◽  
Zero Bias ◽  
Mean Values ◽  
Sem Image ◽  
Abnormal Increase ◽  
Polymer Semiconductor

Abstract A photopolymer based Al/NOA60/p-Si (metal-polymer-semiconductor) MPS device was fabricated and the current transport properties were investigated by using the forward bias current-voltage (I-V) characteristic in the temperature range of 80-300 K. The cross-sectional structure of polymer/semiconductor was revealed by the scanning electron microscope (SEM) image and it was seen that the NOA60 photopolymer was tidily coated on the p-Si surface. According to the I-V measurements at room temperature, the MPS device exhibits a good rectification ratio of 8140 at ±1V. Temperature-dependent I-V measurements (I-V-T) were analyzed on the basis of thermionic emission (TE) theory and an abnormal increase in zero-bias barrier height (BH) and a decrease in ideality factor (n) was observed with increasing temperature. Additionally, two different linear regions with distinct values from the theoretical value of the Richardson constant (A*) were observed in the conventional Richardson plot. Such deviations from ideal TE theory has been attributed to the effect of BH inhomogeneities. Gaussian distribution (GD) of BH model has applied the I-V-T results and double GD BH with mean values of 0.75±0.08 eV (80 – 140 K) and 1.02±0.11 eV (140 – 300 K) were calculated. Moreover, the A* value of 64.73 A/cm2K2 was calculated close to the known value of p-Si from the modified Richardson plot. Thus, it has been concluded that the current transport of the Al/NOA60/p-Si MPS device can be explained by TE with double GD BH model for a wide temperature region.

Electrical Study of Schottky Barriers on Cleaved InP and GaAs (110) Surfaces

1985 ◽  
Vol 54 ◽  
Author(s):  
N. Newman ◽  
M. van Schilfgaarde ◽  
T. Kendelewicz ◽  
W. E. Spicer
Keyword(s):  
Barrier Height ◽  
Ideality Factor ◽  
High Vacuum ◽  
Forward Bias ◽  
Thermionic Emission ◽  
Ultra High Vacuum ◽  
Leakage Currents ◽  
Current Voltage ◽  
Measuring Techniques

We have performed a systematic study of the electrical properties of a large number of metal/n-GaAs and metal/n-InP diodes. Diodes were fabricated on clean cleaved InP and GaAs (110) surfaces in ultra-high vacuum with in-situ metal deposition of Cr, Mn, Sn, Ni, Al, Pd, Cu, Ag and Au. Using current-voltage (I-V) and capacitance-voltage (C-V) measuring techniques, we were able to obtain very reliable and consistent determinations of the barrier height, θ/b, and ideality factor, n. All of the metal-semiconductor systems formed on lightly doped (< 5×1016/cm3) substrates were characterized by near-unity (1.05) ideality factors.The effects of doping on the electrical characteristics of the n-GaAs diodes were investigated. A decrease in the effective I-V barrier height, an increase in the ideality factor in forward bias and a strong voltage dependence on the thermionic emission currents in reverse bias were found for diodes formed on the more heavily doped samples. These changes are essentially metal-independent, but depend strongly on the doping of the substrate. The characterization (and elimination in some cases) of peripheral leakage currents from the thermionic emission current for the n-GaAs systems was found to be essential in obtaining consistent results in our work and in reinterpreting some of the prior work in the literature. The dominant leakage current in the GaAs diodes flows through a small area, low barrier at the periphery of the device and can be eliminated by mesa etching.

A comparative study on the electrical parameters of Au/n-Si Schottky diodes with and without interfacial (Ca1.9Pr0.1Co4Ox) layer

2016 ◽  
Vol 30 (16) ◽  
pp. 1650090 ◽  
Author(s):  
A. Kaya ◽  
H. G. Çetinkaya ◽  
Ş. Altındal ◽  
İ. Uslu
Keyword(s):  
Barrier Height ◽  
Room Temperature ◽  
Voltage Dependence ◽  
Schottky Diodes ◽  
Forward Bias ◽  
Surface States ◽  
Electrical Parameters ◽  
Distribution Profile ◽  
Text Data ◽  
Energy Density Distribution

In order to compare the main electrical parameters such as ideality factor [Formula: see text], barrier height (BH) [Formula: see text], series [Formula: see text] and shunt [Formula: see text] resistances and energy density distribution profile of surface states [Formula: see text], the [Formula: see text]-[Formula: see text] (MS) Schotthy diodes (SDs), with and without interfacial [Formula: see text] layer were obtained from the current–voltage [Formula: see text]–[Formula: see text] measurements at room temperature. The other few electrical parameters such as Fermi energy level [Formula: see text], BH [Formula: see text]), [Formula: see text] and voltage dependence of [Formula: see text] profile were also obtained from the capacitance–voltage [Formula: see text]–[Formula: see text] measurements. The voltage dependence of [Formula: see text] profile has two distinctive peaks in the depletion region for two diodes and they were attributed to a particular distribution of [Formula: see text] located at metal–semiconductor (MS) interface. All of these results have been investigated at room temperature and results have been compared with each other. Experimental results confirmed that interfacial [Formula: see text] layer enhanced diode performance in terms of rectifier rate [Formula: see text] at [Formula: see text], [Formula: see text] [Formula: see text]at [Formula: see text] and [Formula: see text] [Formula: see text] with values of 265, [Formula: see text] and [Formula: see text] for MS type Schottky barrier diode and [Formula: see text], [Formula: see text] and [Formula: see text] for metal–insulator–semiconductor (MIS) type SBD, respectively. It is clear that the rectifying ratio of MIS type SBD is about 9660 times greater than MS type SBD. The value of barrier height (BH) obtained from [Formula: see text]–[Formula: see text] data is higher than the forward bias [Formula: see text]–[Formula: see text] data and it was attributed to the nature of measurements. These results confirmed that the interfacial [Formula: see text] layer has considerably improved the performance of SD.

Sign in / Sign up

Export Citation Format

Share Document