AVS 45th International Symposium
    Vacuum Technology Division Wednesday Sessions
       Session VT-WeM

Paper VT-WeM3
Electron Beam Degradation of Sulfide-Based Thin Film Phosphors for Field Emission Flat Panel Displays

Wednesday, November 4, 1998, 9:00 am, Room 329

Session: Vacuum Microelectronics
Presenter: B.L. Abrams, University of Florida, Gainesville
Authors: B.L. Abrams, University of Florida, Gainesville
T.A. Trottier, Motorola
H.C. Swart, University of the Orange Free State, Republic of South Africa
E.S. Lambers, University of Florida, Gainesville
P.H. Holloway, University of Florida, Gainesville
Correspondent: Click to Email
The change in cathodoluminescence (CL) brightness and changes in surface chemistry of the thin film phosphor, SrS:Ce, have been investigated using a scanning Auger electron spectrometer and an Orial optical spectrometer. The data for SrS:Ce were compared to ZnS:Cu,Cl,Au and Y@sub 2@O@sub 2@S:Eu powders all collected in a stainless steel UHV chamber with gas pressures of 10@super -6@ Torr O@sub 2@. In the presence of a 2kV primary electron beam, the amounts of C and S on the surface decreased while the oxygen concentration increased. As a result, ZnO, Y@sub 2@O@sub 3@ and preumably SrO@sub x@ formed. This change in surface chemistry coincided with a decrease in CL brightness. SrS degraded much faster than ZnS of Y@sub 2@O@sub 2@S. The model for this degradatin process suggests that the primary electron beam dissociated physisorbed molecules to reactive atomic species. These atomic species reacted with surface S and C, carrying them away and leaving behind an increasingly more impenetrable layer. Threshold voltage experiments were conducted to reveal where it becomes possible to measure the CL. This threshold voltage should be affected by the oxide layer discussed above. The implications for vacuums in an FED FPD will be discussed. This work was supported by Darpa grant MDA 972-93-1-0030 through the Phosphor Technology Center of Excellence