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Preparation and characterization of tin oxide films by ion-assisted deposition

Book ·
OSTI ID:549823
; ; ; ; ;  [1];  [2]
  1. Korea Inst. of Science and Technology, Seoul (Korea, Republic of). Div. of Ceramics
  2. Yonsei Univ., Seoul (Korea, Republic of). Dept. of Ceramic Engineering

Undoped tin oxide films were grown on Si substrates by a reactive ion-assisted deposition technique in which oxygen ions were irradiated on depositing Sn particles. In order to investigate the oxidation from SnO to SnO{sub 2}, the effects of initial oxygen contents and heat treatment on the final crystalline structure of tin oxide films were thoroughly examined. Oxygen to Sn metal ratio (N{sub O}/N{sub Sn}) of as-deposited films were controlled from 1.1 to 1.9 by varying the relative arrival ratio ({Gamma}) of oxygen ion to Sn particle from 0.025 to 0.1. Heat treatment was carried out in two different ways; one was post vacuum-annealing at 400--600 C and the other was in-situ annealing 400--500 C. Crystalline structure of as-deposited tin oxide films at room temperature was amorphous. After post-annealing at 400 C, only SnO phase was found below N{sub O}/N{sub Sn} = 1.6 in x-ray diffract ion and crystalline structure of the films comprising higher oxygen contents still appeared to be amorphous. Even though the films still showed SnO phase until {Gamma}50 after 500 C post-annealing, however, mixed structures of SnO, SnO{sub 2}, and intermediate Sn{sub 2}O{sub 3}/Sn{sub 3}O{sub 4} were observed for the films {Gamma}75 and {Gamma}100 with higher oxygen contents. At 600 C annealing, perfect SnO{sub 2} phase was attained for the films having N{sub O}/N{sub Sn} = 1.9. On the other hand, pure polycrystalline SnO{sub 2} films could be obtained by in-situ annealing at low temperature. The values of N{sub O}/N{sub Sn} and the chemical shifts with the variation of oxidation were carefully determined by the comparison of Sn MNN and O KLL Auger transitions. Surface microstructure of deposited films was also analyzed using a scanning electron microscopy (SEM) and an atomic force microscope (AFM).

OSTI ID:
549823
Report Number(s):
CONF-961202--; ISBN 1-55899-342-8
Country of Publication:
United States
Language:
English