Microstructural differences in thin film ZnGa{sub 2}O{sub 4}:Mn phosphor produced by differences in sputtering gas pressure

Journal Article · Wed Nov 15 04:00:00 EST 2006 · Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films

DOI:https://doi.org/10.1116/1.2359737· OSTI ID:20853804

Kim, Joo Han; Holloway, Paul H ^[1]

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1. Department of Advanced Materials Engineering, Chungbuk National University, 12 Gaeshin-dong, Heungduk-gu, Cheongju, Chungbuk 361-763 (Korea, Republic of)

The authors report on the microstructural characteristics of sputter-deposited thin film ZnGa{sub 2}O{sub 4}:Mn phosphors, with an emphasis on the role of energetic particle bombardment. The thin film ZnGa{sub 2}O{sub 4}:Mn phosphors were deposited by radio frequency planar magnetron sputtering of a 2 mol % Mn-doped ZnGa{sub 2}O{sub 4} target in an Ar-O{sub 2} gas mixture at gas pressures ranging from 2 to 20 mTorr. The growth rate of the ZnGa{sub 2}O{sub 4}:Mn films was decreased from 40 to 23 A/min as the gas pressure was raised due to both increased gas-phase scattering as well as reduced target self-bias voltage. Owing to the thermalization of impinging energetic particles and the randomization in their incidence directions when arriving at the substrate, the ZnGa{sub 2}O{sub 4}:Mn films produced at an elevated gas pressure exhibited a porous composite microstructure in which larger columns consisted of bundles of smaller columns separated by voided boundaries. Energetic particle bombardment of the growing film surface at a low gas pressure yielded a densely packed zone-T-type microstructure due to porosity annihilation by knock-on processes and bombardment-enhanced adatom mobility. Atomic force microscopy and grazing incidence x-ray reflectivity data revealed that as the gas pressure was decreased from 20 to 2 mTorr, the rms surface roughness of the deposited ZnGa{sub 2}O{sub 4}:Mn films was reduced from 4.95 to 1.23 nm and the film density increased from 5.314 to 5.681 g/cm{sup 3}, consistent with the postulated effects of energetic particle bombardment upon film microstructure.

• OSTI ID: 20853804
• Journal Information: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films, Journal Name: Journal of Vacuum Science and Technology. A, International Journal Devoted to Vacuum, Surfaces, and Films Journal Issue: 6 Vol. 24; ISSN 1553-1813
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ATOMIC FORCE MICROSCOPY
DOPED MATERIALS
MAGNETRONS
MANGANESE
MICROSTRUCTURE
PHOSPHORS
POROSITY
POROUS MATERIALS
RADIOWAVE RADIATION
REFLECTIVITY
ROUGHNESS
SPUTTERING
SURFACES
THERMALIZATION
THIN FILMS
X RADIATION