Combinatorial characterization of transparent conductive properties of Ga-doped ZnO films cosputtered from electron cyclotron resonance and rf magnetron plasma sources

Journal Article · Mon Mar 15 00:00:00 EDT 2010 · Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films

DOI:https://doi.org/10.1116/1.3328053· OSTI ID:22053931

Akazawa, Housei ^[1]

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1. NTT Microsystem Integration Laboratories, 3-1 Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198 (Japan)

The simultaneous sputtering of ZnO and Ga{sub 2}O{sub 3} by electron cyclotron resonance and rf magnetron plasma sources produced Ga-doped ZnO (GZO) films with continuously varying Ga concentration over the substrate surface. Combinatorial evaluation of electrical and optical properties of GZO film grown on silica glass substrate without heater annealing enabled identification of minimum resistivity (0.5 m{Omega} cm) at a Ga{sub 2}O{sub 3} content of 5.5 wt % with an optical transmittance of 90% in the visible wavelength. The monotonically decreasing mobility that was associated with increasing carrier concentration as Ga{sub 2}O{sub 3} content was increased indicated that conduction was governed by ionized impurity scattering. Above the critical Ga{sub 2}O{sub 3} content (6 wt %), carrier concentration decreased since excess Ga atoms that were incorporated beyond the solubility limit at Zn sites hindered large crystalline domains from forming. The ZnO (002) x-ray diffraction peak was suppressed and peaks assigned to Ga{sub 2}O{sub 3} were observed at high Ga{sub 2}O{sub 3} content. The optimum Ga{sub 2}O{sub 3} content shifted to 3.5 wt % at a deposition temperature of 200 deg. C and 2.5 wt % at 300 deg. C, and the minimum resistivity was further decreased to 0.28 m{Omega} cm at 200 deg. C. However, the resistivities at these elevated temperatures were incredibly high both at the lower and higher side of the optimum Ga{sub 2}O{sub 3} content.

• OSTI ID: 22053931
• Journal Information: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Vol. 28, Issue 2; Other Information: (c) 2010 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1553-1813
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
CARRIER DENSITY
CRYSTAL GROWTH
DEPOSITION
DOPED MATERIALS
ELECTRON CYCLOTRON-RESONANCE
GALLIUM OXIDES
GLASS
IMPURITIES
MAGNETRONS
OPACITY
PLASMA
RF SYSTEMS
SEMICONDUCTOR MATERIALS
SILICA
SPUTTERING
SUBSTRATES
THIN FILMS
X-RAY DIFFRACTION
ZINC OXIDES