scholarly journals Ohmic contacts to n-type germanium with low specific contact resistivity

2012 ◽  
Vol 100 (2) ◽  
pp. 022113 ◽  
Author(s):  
K. Gallacher ◽  
P. Velha ◽  
D. J. Paul ◽  
I. MacLaren ◽  
M. Myronov ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Contact Resistivity ◽  
Specific Contact ◽  
Specific Contact Resistivity

A Microstructual Analysis of Au/Pd/Ti Ohmic Contacts for GaAs-Based Heterojunction Bipolar Transistors (HJBTs)

1991 ◽  
Vol 240 ◽  
Author(s):  
Bernard M. Henry ◽  
A. E. Staton-Bevan ◽  
V. K. M. Sharma ◽  
M. A. Crouch ◽  
S. S. Gill
Keyword(s):  
Structural Properties ◽  
Heterojunction Bipolar Transistors ◽  
Ohmic Contacts ◽  
Heat Treatments ◽  
Bipolar Transistors ◽  
Contact Resistivity ◽  
Base Region ◽  
Specific Contact ◽  
Specific Contact Resistivity ◽  
Contact Resistivities

ABSTRACTAu/Pd/Ti and Au/Ti/Pd ohmic structures to thin p+-GaAs layers have been investigated for use as contacts to the base region of HJBTs. The Au/Pd/Ti contact system yielded specific contact resistivities at or above 2.8 × 10−5Ω:cm2. Heat treatments up to 8 minutes at 380°C caused only limited interaction between the metallization and the semiconductor. The metal penetrated to a maximum depth of ≃2nm. Specific contact resistivity values less than 10−5Ωcm2 were achieved using the Au/Ti/Pd (400/75/75nm) scheme. The nonalloyed Au/Ti/Pd contact showed the best combination of electrical and structural properties with a contact resistivity value of 9 × 10≃6Ωcm2 and Pd penetration of the GaAs epilayer to a depth of cs30nm.

Investigation of Cu-Ge/Gaas Metal-Semiconductor Interfaces for Low Resistance Ohmic Contacts

1996 ◽  
Vol 448 ◽  
Author(s):  
Serge Oktyabrsky ◽  
M.A. Borek ◽  
M.O. Aboelfotoh ◽  
J. Narayan
Keyword(s):  
Interfacial Layer ◽  
Ohmic Contacts ◽  
High Thermal Stability ◽  
Contact Resistivity ◽  
Polycrystalline Layer ◽  
Ohmic Behavior ◽  
Semiconductor Interfaces ◽  
Transmission Electron ◽  
Specific Contact ◽  
Specific Contact Resistivity

AbstractChemistry and interfacial reactions of the Cu-Ge alloyed ohmic contacts to n-GaAs with extremely low specific contact resistivity (6.5×10-7 Ω·cm2 for n~1017 cm-3) have been investigated by transmission electron microscopy, EDX and SIMS. Unique properties of the contact layers are related to the formation (at Ge concentration above 15 at.%) of a polycrystalline layer of ordered orthorhombic ε1-Cu3Ge phase. Formation of the ε1-phase is believed to be responsible for high thermal stability, interface sharpness and uniform chemical composition. The results suggest that the formation of the ζ- and ε1,-Cu3Ge phases creates a highly Ge-doped n+-GaAs interfacial layer which provides the low contact resistivity. Layers with Ge deficiency to form ζ-phase show nonuniform intermediate layer of hexagonal β-Cu3As phase which grows epitaxially on Ga{111} planes of GaAs. In this case, released Ga diffuses out and dissolves in the alloyed layer stabilizing the ζ-phase which is formed in the structures with average Ge concentration of as low as 5 at.%. These layers also exhibit ohmic behavior.

Cr/Ni/Au ohmic contacts to the moderately doped p- and n-GaN

1996 ◽  
Vol 449 ◽  
Author(s):  
Taek Kim ◽  
Myung C. Yoo ◽  
Taeil Kim
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Ohmic Contacts ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Contact Resistivity ◽  
Sapphire Substrates ◽  
Specific Contact ◽  
Specific Contact Resistivity ◽  
Metalorganic Chemical

ABSTRACTWe report new Cr/Ni/Au and Ni/Cr/Au tri-layer metallization schemes for achieving low resistance ohmic contacts to moderately doped p- (∼1 × 1017/cm3), and n-GaN (∼1 × 1018/cm3) respectively. The metallizations were thermally evaporated on 2 μm-thick GaN layers grown on c-plane sapphire substrates by metalorganic chemical vapor deposition (MOCVD). Comparisons with bi-layer metallizations such as Ni/Au and Cr/Au were also made. The Cr/Ni/Au contacts showed a low specific contact resistivity of 9.1 × 10−5 Ω⋅cm2 to n-GaN while that of Ni/Cr/Au to p-GaN was 8.3 × 10−2 Ω⋅cm2. The Ni/Cr/Au contacts also showed a low specific contact resistivity of 2.6 × 10−4 Ω⋅cm2 to n-GaN. The Ni/Cr/Au metallization could made reasonable ohmic contacts to p- and n-GaN simultaneously

Microstructure, electrical properties, and thermal stability of Au-based ohmic contacts to p-GaN

1997 ◽  
Vol 12 (9) ◽  
pp. 2249-2254 ◽  
Author(s):  
L. L. Smith ◽  
R. F. Davis ◽  
M. J. Kim ◽  
R. W. Carpenter ◽  
Y. Huang
Keyword(s):  
High Temperature ◽  
Ohmic Contacts ◽  
Microstructural Characterization ◽  
Secondary Phase ◽  
High Resolution Electron Microscopy ◽  
Contact Resistivity ◽  
Cross Sectional ◽  
Ohmic Behavior ◽  
Specific Contact ◽  
Specific Contact Resistivity

The work described in this paper is part of a systematic study of ohmic contact strategies for GaN-based semiconductors. Gold contacts exhibited ohmic behavior on p-GaN when annealed at high temperature. The specific contact resistivity (ρc) calculated from TLM measurements on Au/p-GaN contacts was 53 Ω · cm2 after annealing at 800 °C. Multilayer Au/Mg/Au/p-GaN contacts exhibited linear, ohmic current-voltage (I-V) behavior in the as-deposited condition with ρc = 214 Ω · cm2. The specific contact resistivity of the multilayer contact increased significantly after rapid thermal annealing (RTA) through 725 °C. Cross-sectional microstructural characterization of the Au/p-GaN contact system via high-resolution electron microscopy (HREM) revealed that interfacial secondary phase formation occurred during high-temperature treatments, which coincided with the improvement of contact performance. In the as-deposited multilayer Au/Mg/Au/p-GaN contact, the initial 32 nm Au layer was found to be continuous. However, Mg metal was found in direct contact with the GaN in many places in the sample after annealing at 725 °C for 15 s. The resultant increase in contact resistance is believed to be due to the barrier effect increased by the presence of the low work function Mg metal.

Specific Contact Resistivity Improvement by As Preamorphization Implantation for Ti-Based Ohmic Contacts on n+-Si

2020 ◽  
Vol 67 (4) ◽  
pp. 1726-1729 ◽  
Author(s):  
Shujuan Mao ◽  
Chao Zhao ◽  
Jinbiao Liu ◽  
Guilei Wang ◽  
Menghua Li ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Contact Resistivity ◽  
Specific Contact ◽  
Specific Contact Resistivity

Low Resistance Contacts to P-Type GaN

1997 ◽  
Vol 468 ◽  
Author(s):  
Taek Kim ◽  
Jinseok Khim ◽  
Suhee Chae ◽  
Taeil Kim
Keyword(s):  
Vapor Deposition ◽  
Ohmic Contacts ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Contact Resistivity ◽  
Low Resistance ◽  
Sapphire Substrates ◽  
Specific Contact ◽  
Specific Contact Resistivity ◽  
P Type

ABSTRACTWe report the low resistance ohmic contacts to p-GaN using a Pd/Au bimetal scheme. A specific contact resistivity of 9.1 × 10-3 Ω-cm2 was obtained after annealing. The metallization was e-beam evaporated on 2 μm-thick p-GaN (∼ 9 × 1016/cm3) layers grown on c-plane sapphire substrates by metalorganic chemical vapor deposition (MOCVD). The comparison with other contacts showed that the contact resistivity of the Pd/Au contacts was at least one order smaller than those of Pt/Au and Ni/Au contacts.

Two-contact Circular Test Structure for Determining Specific Contact Resistivity

2013 ◽  
Vol 1553 ◽  
Author(s):  
Y. Pan ◽  
G. K. Reeves ◽  
P. W. Leech ◽  
P. Tanner ◽  
A. S. Holland
Keyword(s):  
Ohmic Contacts ◽  
Electrical Characterization ◽  
Contact Resistivity ◽  
Test Structure ◽  
Metal Contacts ◽  
Circular Test ◽  
Specific Contact ◽  
Specific Contact Resistivity ◽  
Analytical Expressions ◽  
Geometrical Dimensions

ABSTRACTAs ohmic contacts decrease in size and approach nanoscale dimensions, accurate electrical characterization is essential, requiring the development of suitable test structures for this task. We present here a new test structure derived from the standard three-contact circular transmission line model (CTLM) [1], for determining the specific contact resistivity of ohmic contacts. This test structure minimizes sources of error which arise from the CTLM by – (i) reducing the number of contacts within one test pattern from three to two, (ii) ensuring the assumption of equipotential metal contacts used in modelling is more easily attained experimentally, and (iii) allowing the fabrication of reduced geometrical dimensions essential for determining low specific contact resistivity values. The analytical expressions are presented and experiment results are undertaken to demonstrate the accuracy of the technique. There are no error corrections required for determining contact parameters using the presented test structure.

Assessing Ohmic Contacts

1992 ◽  
Vol 260 ◽  
Author(s):  
H Barry Harrison ◽  
Geoffery K Reeves
Keyword(s):  
Ohmic Contacts ◽  
Measurement Accuracy ◽  
Contact Resistivity ◽  
Semiconducting Materials ◽  
Specific Contact ◽  
Specific Contact Resistivity

ABSTRACTThis paper reviews specific contact resistivity pc values obtained theoretically and experimently for a range of semiconducting materials. Techniques of obtaining pc values in terms of measurement, accuracy and reproducibility are then considered and matched to the semiconducting materials previously covered.

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