AVS 46th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoP

Paper TF-MoP13
Properties of Indium Oxide Thin Films Prepared by Reactive Electron Beam Evaporation Technique for EMI Control

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: J. Asbalter, Indian Institute of Technology, India
Authors: J. Asbalter, Indian Institute of Technology, India
A. Subrahmanyam, Indian Institute of Technology, India
Correspondent: Click to Email
It is well known that transparent conductors like Indium oxide (IO) are good Electro Magnetic Interference (EMI) shields. In the present investigation, the EMI shielding property of indium oxide thin films has been studied as a function of growth temperature. All the IO films are grown on glass substrates by reactive electron beam evaporation technique at a chamber pressure (with the reactive gas, oxygen) of 2.5 x 10@super -4@ milli bar. The substrate temperature is varied between 160@super o@C - 200@super o@C. All the films show metallic properties (carrier concentration, N = 10@super 19@/cc, Hall Mobility =20-30 cm@super 2@ V@super -1@ sec@super -1@) with an optical transmission above 85% (at 500 nm wavelength). It is found that the EMI shielding efficiency (SE) of IO films (of 100 nm thickness) is very much comparable to that of the silver coated metal sheet in the measured frequency range 1 MHz till 100 MHz . As is well known that high frequecny shielding is related to the plasma frequency and the low frequency shielding is dependant on the magnetic properties. The AC (magnetic) susceptibility of the films measured in the temperature range 300 K till 6 K show very interesting magnetic properties. All the films show diamagnetic behavior at room temperature (300 K). For the films prepared at 200@super o@C, there is a clear paramagnetic behavior below 250 K. Present work analyses the reasons for the paramagnetic nature and its consequence on the low frequency (< 10 MHz) shielding efficiency.