Laser-Annealed Gap Ohmic Contacts for High-Temperature Devices

1980 ◽  
Vol 1 ◽  
Author(s):  
O. Eknoyan ◽  
W. Van Der Hoeven ◽  
T. Richardson ◽  
W.A. Porter
Keyword(s):  
High Temperature ◽  
Surface Morphology ◽  
Nd:Yag Laser ◽  
Ohmic Contacts ◽  
Electrical Characteristics

ABSTRACTThe results of successful Nd:YAG laser annealed ohmic contacts on n-type GaP are reported. Comparisons on identical laser and thermal annealed contacts on the same substrates are performed. In addition aging investigations are also studied. The results indicate that laser annealed contacts have far superior electrical characteristics, much better surface morphology and are substantially more stable with aging than the same but thermally alloyed ones.

Electrical Properties of Homoepitaxial Diamond Films

1989 ◽  
Vol 162 ◽  
Author(s):  
G. Sh. Gildenblat ◽  
S. A. Grot ◽  
C. W. Hatfield ◽  
C. R. Wronski ◽  
A. R. Badzian ◽  
...  
Keyword(s):  
Thin Film ◽  
High Temperature ◽  
Ohmic Contacts ◽  
Schottky Diodes ◽  
Diamond Films ◽  
Diamond Surface ◽  
Electrical Characteristics ◽  
Boron Doped ◽  
Process Formation ◽  
Conductive State

ABSTRACTWe describe the electrical characteristics of boron doped homoepitaxial diamond films fabricated using a plasma assisted CVD process, formation of ohmic contacts, high temperature (580°C) Schottky diodes, and a rudimentary diamond MESFET. We also report reversible changes of the conductive state of the diamond surface by various surface treatments for both natural and thin-film diamonds.

Electric and Morphology Studies of Ohmic Contacts on AlGaN/GaN

2000 ◽  
Vol 622 ◽  
Author(s):  
V. Tilak ◽  
R. Dimitrov ◽  
M. Murphy ◽  
B. Green ◽  
J. Smart ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Contact Resistance ◽  
High Power ◽  
Ohmic Contacts ◽  
Critical Parameter ◽  
Electrical Contacts ◽  
Electrical Characteristics ◽  
Optimum Ratio ◽  
Transfer Resistance

ABSTRACTAlGaN/GaN is a promising system for high power electron devices. Quality of ohmic contacts is a critical parameter in determining the performance of the device. Although we have achieved a transfer resistance (Rc) of 0.35Δmm and ρc of 9.5×10−7 Δcm−2 the morphology and edge acuity of the contacts are poor. The standard ohmic contact recipes consist of a combination of Titanium and Aluminum with Nickel and/or Gold. This is annealed at 800°C-950°C [1-5]. In this work we study ohmic contacts on unintentionally doped Al0.3Ga0.7N/GaN system. We look at ratios of Ti/Al from 0 to 2 to determine which is the optimum ratio in terms of surface morphology and electrical characteristics. From our studies we conclude that morphology of a Ti/Al contact is good over a ratio of 0.3 and the contact resistance is minimized at a Ti/Al of 0.6. The ohmic contacts are improved electrically if a layer of gold is added on top. The best electrical contacts however were obtained with a four layer recipe of Ti/Al/Ti/Au, which gave contact resistance (Rc) around 0.45Δmm, but the morphology of the contacts was poor.

Electrical Characteristics and Surface Morphology for Arsenic Ion-Implanted 4H-SiC at High Temperature

2000 ◽  
Vol 338-342 ◽  
pp. 865-868 ◽  
Author(s):  
Junji Senzaki ◽  
Kenji Fukuda ◽  
Seiji Imai ◽  
Yasunori Tanaka ◽  
Naoto Kobayashi ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Morphology ◽  
Electrical Characteristics ◽  
Ion Implanted

Surface morphology of ion-beam deposited carbon films under high temperature

2002 ◽  
Vol 20 (6) ◽  
pp. 2072
Author(s):  
Meiyong Liao ◽  
Chunlin Chai ◽  
Shaoyan Yang ◽  
Zhikai Liu ◽  
Fuguang Qin ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Morphology ◽  
Ion Beam ◽  
Carbon Films

Current Transport in Ti/Al/Ni/Au Ohmic Contacts to GaN and AlGaN

2007 ◽  
Vol 556-557 ◽  
pp. 1027-1030 ◽  
Author(s):  
Ferdinando Iucolano ◽  
Fabrizio Roccaforte ◽  
Filippo Giannazzo ◽  
A. Alberti ◽  
Vito Raineri
Keyword(s):  
Contact Resistance ◽  
Field Emission ◽  
Ohmic Contacts ◽  
Theoretical Models ◽  
Specific Contact Resistance ◽  
Strong Increase ◽  
Current Transport ◽  
Electrical Characteristics ◽  
Structural And Electrical Properties ◽  
Specific Contact

In this work, the structural and electrical properties of Ti/Al/Ni/Au contacts on n-type Gallium Nitride were studied. An ohmic behaviour was observed after annealing above 700°C. The structural analysis showed the formation of an interfacial TiN layer and different phases in the reacted layer (AlNi, AlAu4, Al2Au) upon annealing. The temperature dependence of the specific contact resistance demonstrated that the current transport occurs through thermoionic field emission in the contacts annealed at 600°C, and field emission after annealing at higher temperatures. By fitting the data with theoretical models, a reduction of the Schottky barrier from 1.21eV after annealing at 600°C to 0.81eV at 800°C was demonstrated, together with a strong increase of the carrier concentration at the interface. The reduction of the contact resistance upon annealing was discussed by correlating the structural and electrical characteristics of the contacts.

Structural and electrical characteristics of Ga2O3(Gd2O3)∕GaAs under high temperature annealing

2006 ◽  
Vol 100 (10) ◽  
pp. 104502 ◽  
Author(s):  
C. P. Chen ◽  
Y. J. Lee ◽  
Y. C. Chang ◽  
Z. K. Yang ◽  
M. Hong ◽  
...  
Keyword(s):  
High Temperature ◽  
Electrical Characteristics ◽  
High Temperature Annealing

Characteristics and aging of SiC MOSFETs operated at very high temperatures

2014 ◽  
Vol 1693 ◽  
Author(s):  
Dean P. Hamilton ◽  
Michael R. Jennings ◽  
Craig A. Fisher ◽  
Yogesh K. Sharma ◽  
Stephen J. York ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Threshold Voltage ◽  
Thermal Aging ◽  
Ohmic Contacts ◽  
Stress Tests ◽  
Temperature Capability ◽  
Temperature Constant ◽  
Voltage Management ◽  
Very High

ABSTRACTSilicon carbide power devices are purported to be capable of operating at very high temperatures. Current commercially available SiC MOSFETs from a number of manufacturers have been evaluated to understand and quantify the aging processes and temperature dependencies that occur when operated up to 350°C. High temperature constant positive bias stress tests demonstrated a two times increase in threshold voltage from the original value for some device types, which was maintained indefinitely but could be corrected with a long negative gate bias. The threshold voltages were found to decrease close to zero and the on-state resistances increased quite linearly to approximately five or six times their room temperature values. Long term thermal aging of the dies appears to demonstrate possible degradation of the ohmic contacts. This appears as a rectifying response in the I-V curves at low drain-source bias. The high temperature capability of the latest generations of these devices has been proven independently; provided that threshold voltage management is implemented, the devices are capable of being operated and are free from the effects of thermal aging for at least 70 hours cumulative at 300°C.

Lifetime Enhancement of 4H-SiC PiN Diodes Using High Temperature Oxidation Treatment

2018 ◽  
Vol 924 ◽  
pp. 440-443
Author(s):  
Yeganeh Bonyadi ◽  
Peter M. Gammon ◽  
Olayiwola Alatise ◽  
Roozbeh Bonyadi ◽  
Philip A. Mawby
Keyword(s):  
High Temperature ◽  
Thermal Oxidation ◽  
Carrier Lifetime ◽  
Drift Region ◽  
Electrical Characteristics ◽  
Pin Diodes ◽  
Oxidation Treatment ◽  
Temperature Oxidation ◽  
Bipolar Devices ◽  
Minority Carriers

In this paper, the application of a high temperature thermal oxidation and annealing process to 4H-SiC PiN diodes with 35 μm thick drift regions is explored, the aim of which was to increase the carrier lifetime in the 4H-SiC. Diodes were fabricated using 4H-SiC material and underwent a thermal oxidation in dry pure O2 at 1550◦C followed by an argon anneal at the same temperature. Reverse recovery tests indicated a carrier lifetime increase of around 42% which is due to increase of excessive minority carriers in the drift region. The switching results illustrate that the use of this process is a highly effective and efficient way of enhancing the electrical characteristics of high voltage 4H-SiC bipolar devices.

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