Temperature Behavior of Pt/Au Ohmic Contacts to p-GaN

King, D.; Zhang, L.; Ramer, J.; Hersee, S.D.; Lester, L. F.

doi:10.1557/proc-468-421

Cited by 66 publications

(31 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The GaN:Mg samples were annealed at 800°C for 4 min by rapid thermal annealing ͑RTA͒ under a N 2 atmosphere to activate the Mg acceptors. The net concentration of holes in the film was 3.3ϫ10 17 cm Ϫ3 , and hole mobility was 15.8 cm 2 /V s, as determined using roomtemperature Hall-effect measurements. Before the deposition of Pt on the p-GaN, which was used to form broad area ohmic contacts, the samples were cleaned using ultrasonic baths in beakers of acetone for 5 min and beakers of isopropyl alcohol for 5 min, followed by a deionized ͑DI͒ water rinse for 10 min.…”

Section: Methodsmentioning

confidence: 99%

X-ray photoemission determination of the Schottky barrier height of metal contacts to n–GaN and p–GaN

Rickert

Ellis

Kim

et al. 2002

Journal of Applied Physics

105

View full text Add to dashboard Cite

Synchrotron radiation-based x-ray photoemission spectroscopy was used to study the surface Fermi level position within the band gap for thin metal overlayers of Au, Al, Ni, Ti, Pt, and Pd on n-GaN and p-GaN. Nonequilibrium effects were taken into account by measuring the Fermi edge of the metal overlayer. There are two different behaviors observed for the six metals studied. For Au, Ti, and Pt, the surface Fermi level lies about 0.5-eV higher in the gap for n-type than for p-type GaN. For Ni, Al, and Pd, the surface Fermi level position is independent of doping, but varies from one metal to the other. Results for Ni, Pd, and Al fit a modified Schottky-Mott theory, while Au, Ti, and Pt demonstrate a more complex behavior. Atomic force microscopy was used along with photoemission to investigate the growth mode of each metal on the GaN surface.

show abstract

Section: Methodsmentioning

confidence: 99%

X-ray photoemission determination of the Schottky barrier height of metal contacts to n–GaN and p–GaN

Rickert

Ellis

Kim

et al. 2002

Journal of Applied Physics

105

View full text Add to dashboard Cite

show abstract

“…and Pd/Au 3,4 with oxygen annealing. In the past, several other metal combinations, such as Au, 5,6 Ni, 7,8 Pd, 9 Pt, 7,10 Ni/Au, [10][11][12][13][14] and Pt/Ni/Au, 15,16 have also been studied. Lee and co-workers 4 reported on the surface treatment using boiling aquaregia.…”

mentioning

confidence: 99%

Very-low-specific-resistance Pd/Ag/Au/Ti/Au alloyed ohmic contact to p GaN for high-current devices

Adivarahan¹,

Lunev

Khan

et al. 2001

Applied Physics Letters

View full text Add to dashboard Cite

We report on Pd/Ag/Au/Ti/Au alloyed metallic contact to p GaN. An 800 °C anneal for 1 min in flowing nitrogen ambient produces an excellent ohmic contact with a specific contact resistivity close to 1×10−6 Ω cm2 and with good stability under high current operation conditions. This high-temperature anneal forms an alloy between Ag, Au, and p GaN resulting in a highly p-doped region at the interface. Using x-ray photoelectron spectroscopy and x-ray diffraction analysis, we confirm that the contact formation mechanism is the metal intermixing and alloying with the semiconductor.

show abstract

“…[4][5][6][7][8][9][10][11] This strategy is based on the Schottky model, which predicts that higher work function metals will result in lower Schottky barriers to p-type semiconductors. The limited experimental evidence available on metal/p-GaN contacts suggests that the Schottky model is at least partially applicable.…”

Section: Introductionmentioning

confidence: 99%

“…4 Of the several contact schemes to p-GaN that have been studied Au/Ni contacts have received the most attention. Despite being used in devices, the Au/Ni contacts typically exhibit a specific contact resistance (ρ c ) in the range of 10 -3 and 10 -2 Ω cm 2 range 7,8,12 and show poor thermal stability. 13 However, it is known that the specific contact resistance of p-GaN depends on many factors such as the quality of the bulk substrate and its surface preparation and processing conditions.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

NiIn as an Ohmic Contact to P-GaN

Ingerly

Chang

Chen

1999

MRS Internet j. nitride semicond. res.

View full text Add to dashboard Cite

ABSRTACTBased on the criteria for the solid state exchange reaction with p-GaN, we have investigated the intermetallic compound NiIn as a possible ohmic contact. The contacts were fabricated by depositing NiIn on p-GaN films (p ~ 2 x 10 17 cm -3 ) using RF sputtering from a compound target. The as-deposited, NiIn contacts were found to be rectifying and using I-V characterization a Schottky barrier height of 0.82 eV was measured. Rapid thermal annealing of the contacts was shown to significantly decrease their resistance, with contacts annealed at 800°C for 1 min yielding the lowest resistance. When annealed at 800 °C for 1 min NiIn contacts exhibited a specific contact resistance of 8-9 x 10 -3 Ω cm 2 , as measured by the circular transmission line model. To allow a more universal comparison the more traditional Ni/Au contacts, processed under the same conditions, were used as a standard. Their measured specific contact resistance (ρ c = 1.2 -2.1 x 10 -2 Ω cm 2 ) was significantly higher than that of the NiIn contacts. Demonstrating that NiIn has promise as an ohmic contact to p-GaN and should be studied in greater detail. INTRODUCTIONIt has long been realized that the III-V nitrides have tremendous potential for optoelectronic devices operating in the blue and UV wavelengths as well as for use in high power-high temperature semiconductor devices. The III-V nitrides form a continuous alloy system whose direct band gap ranges from 6.2 eV (AlN) to 3.4 eV (GaN) to 1.9 eV (InN) at room temperature.1 This potentially allows the fabrication of high efficiency optical devices, such as Light Emitting Diodes (LEDs), which can operate from orange to the UV region. The extension into the green and blue wavelengths completes the visible spectrum allowing semiconductor technology to be used for applications such as large full color displays and traffic lights. 2,3Early research into the nitrides outlined several problem areas, which hindered efforts to produce devices based on III-V nitride technology. Particularly the lack of p-GaN made the fabrication of efficient optical devices based on p-n junctions impossible, though some LEDs based on metal-insulator-semiconductors were fabricated. 1,3 Only recently due to advances in ptype doping has GaN started to realize its potential and there are now nitride based devices available. However, the metal contact to p-GaN is an important concern since high contact resistance will substantially reduce the performance of GaN based devices. In fact, the high resistance of the metal/p-GaN contact is one of the most significant issues limiting laser diode performance.Most of the current work on finding low resistance metallizations to p-GaN has focused on high work function elemental metals deposited in multilayer structures. [4][5][6][7][8][9][10][11] This strategy is based on the Schottky model, which predicts that higher work function metals will result in lower Schottky barriers to p-type semiconductors. on metal/p-GaN contacts suggests that the Schottky model is at least partially a...

show abstract

Temperature Behavior of Pt/Au Ohmic Contacts to p-GaN

Cited by 66 publications

References 9 publications

X-ray photoemission determination of the Schottky barrier height of metal contacts to n–GaN and p–GaN

X-ray photoemission determination of the Schottky barrier height of metal contacts to n–GaN and p–GaN

Very-low-specific-resistance Pd/Ag/Au/Ti/Au alloyed ohmic contact to p GaN for high-current devices

NiIn as an Ohmic Contact to P-GaN

Contact Info

Product

Resources

About