Characterization of Metal/A1xIn1-xN Interface Thermal Stability and Electrical Properties

1996 ◽  
Vol 449 ◽  
Author(s):  
Guohua Qiu ◽  
Fen Chen ◽  
J. O. Olowolafe ◽  
C. P. Swann ◽  
K. M. Unruh ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Specific Contact Resistance ◽  
Nitride Semiconductors ◽  
Group Iii ◽  
Line Measurement ◽  
Solid State Devices ◽  
Specific Contact ◽  
Group Iii Nitride ◽  
The Moment

ABSTRACTThe interfaces between metals and semiconductors are very crucial to the performance and reliability of solid-state devices. At the moment information on the interfaces between metals and group III-nitride semiconductors are very rare. In this study, linear I-V characteristics of titanium and aluminum to A1xIn1-xN of three different composition (x=0.18, 0.50,0.85) were obtained exhibiting ohmic characteristics. Specific contact resistance of these metals to A1.18In.82N and Al.5In.5N was measured by transmission line measurement. Interdiffusion between the metals and the semiconductors, induced by annealing in N2 ambient, was determined using RBS and thermal stability was evaluated.

The Influence of Contact Composition, Pretreatment, and Annealing Gas on the Ohmic Behavior of Ti/Al-Based Ohmic Contacts to n-Al0.4Ga0.6N

2001 ◽  
Vol 680 ◽  
Author(s):  
K. O. Schweitz ◽  
T. G. Pribicko ◽  
S. E. Mohney ◽  
T. F. Isaacs-Smith ◽  
J. Williams ◽  
...  
Keyword(s):  
Ohmic Contacts ◽  
Metal Layer ◽  
Active Role ◽  
Specific Contact Resistance ◽  
X Ray Diffraction ◽  
Group Iii ◽  
Ohmic Behavior ◽  
Annealing Conditions ◽  
Specific Contact ◽  
Group Iii Nitride

ABSTRACTAs the group III nitride semiconductor technology matures, an increasing number of devices are being fabricated with high Al fraction AlGaN. In this study, ohmic behavior is achieved using Ti/Al/Pt/Au contacts to n-Al0.4Ga0.6N, which is the highest Al fraction for which ohmic contact formation has been reported. The effect of contact composition, pretreatment, and annealing conditions is studied by 30 s isochronal annealing experiments between 500°C and 1000°C. A specific contact resistance ρC of (5±3) × 10−5 ωcm2 is obtained using Ti(26 nm)/Al(74 nm)/Pt(50 nm)/Au(50 nm) contacts to n-Al0.4Ga0.6N annealed in N2 at 800°C; however, this value is shown to be artificially high because the metal sheet resistance RM is 4 ω/⊏ causing an artifact in the data analysis. All contacts with ρC < 10−3 ωcm2 exhibit a local minimum in ρC after annealing at 800°C. The observed increase in ρC upon annealing at 850°C and 900°C, however, is not an artifact originating from a change in RM. The top Au layer is found to play an active role in forming ohmic contacts with low ρC, since omitting the Au layer yields an increase in ρC of two orders of magnitude after annealing at 800°C. Furthermore, leaving out the Au layer requires an annealing temperature of 700°C to result in linear I-V curves for currents up to 100 µA, as opposed to 500°C when the Au layer is present. The role of Au is further studied in Ti(26 nm)/Al(74 nm)/Ni(50 nm)/Au(50 nm) contacts, where Rutherford backscattering spectroscopy reveals Ga in the metal layer and/or Au buried deeper than the original semiconductor-metal interface, and x-ray diffraction indicates the formation of new phases to happen concurrently with a decrease in ρC of three orders of magnitude.

Raman scattering characterization of group III-nitride epitaxial layers including cubic phase

1998 ◽  
Vol 189-190 ◽  
pp. 435-438 ◽  
Author(s):  
Hiroshi Harima ◽  
Toshiaki Inoue ◽  
Shin-ichi Nakashima ◽  
Hajime Okumura ◽  
Yuuki Ishida ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Cubic Phase ◽  
Epitaxial Layers ◽  
Group Iii ◽  
Group Iii Nitride

scholarly journals Contact Resistance of InGaN/GaN Light Emitting Diodes Grown on the Production Model Multi-Wafer MOVPE Reactor

1999 ◽  
Vol 4 (S1) ◽  
pp. 703-708 ◽  
Author(s):  
R.W. Chuang ◽  
A.Q. Zou ◽  
H.P. Lee ◽  
Z.J. Dong ◽  
F.F. Xiong ◽  
...  
Keyword(s):  
Contact Resistance ◽  
Transmission Line ◽  
Device Fabrication ◽  
Production Model ◽  
Specific Contact Resistance ◽  
Single Quantum Well ◽  
Light Emitting ◽  
Annealing Temperatures ◽  
Line Measurement ◽  
Specific Contact

We report both the device fabrication and characterization of InGaN/GaN single quantum well LEDs grown on sapphire substrates using multi-wafer MOVPE reactor. To improve current spreading of the LEDs, a self-aligned process is developed to define LED mesa that is coated with a thin, semi-transparent Ni/Au (40 Å/40 Å) layer. A detailed study on the ohmic contact resistance of Ni/Cr/Au on p-GaN versus annealing temperatures is carried out on transmission line test structures. It was found that the annealing temperatures between 300 to 500 °C yield the lowest specific contact resistance rc ( 0.016 Ω-cm2 at a current density of 66.7 mA/cm). Based on the extracted rc from the transmission line measurement, we estimate that the contact resistance of the p-type GaN accounts for ∼ 88% of the total series resistance of the LED.

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.

Spatio-time-resolved cathodoluminescence studies of wide-bandgap group-III nitride semiconductors

2020 ◽  
Vol 59 (2) ◽  
pp. 020501
Author(s):  
Shigefusa F. Chichibu ◽  
Yoichi Ishikawa ◽  
Kouji Hazu ◽  
Kentaro Furusawa
Keyword(s):  
Wide Bandgap ◽  
Nitride Semiconductors ◽  
Time Resolved ◽  
Group Iii ◽  
Group Iii Nitride
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