IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Tuesday Sessions
       Session EL-TuP

Paper EL-TuP13
Electrical Properties of Cd Vapor Pressured CdZnTe for HgCdTe Passivation

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Electronic Materials Poster Session
Presenter: S.Y. An, Korea Institute of Science and Technology
Correspondent: Click to Email
The semiconductor-passivating layer interfaces, as well as the dielectric properties of the passivating layers, play important roles in HgCdTe based photodiodes. Various techniques are being developed to obtain surface passivation layers on HgCdTe, but the thermal or e-beam evaporation methods have become the general approach in this area. When CdZnTe films deposited with an evaporation techniques, it might have a possibility to introduce surface nonstoichometry due to high vapor pressure of group II element. To avoid surface nonstoicheometry in deposited CdZnTe layer, we intentionally exposed Cd overpressure from 1x10@super -4@ torr to 1x10@super -8@ torr when the CdZnTe deposition was carried out. Test structures of Metal-Insulator-Semiconductor were processed and their electrical properties were measured by capacitance-voltage characteristics. For the Cd pressure of 1x10@super -8@ torr, the flat band voltage of MIS capacitor is about -0.3V with fixed charge density of 3.0x10@super 10@/cm@super -3@ and hysteresis was drastically reduced. We found that Cd vapor pressured CdZnTe passivation layer have much lower fixed charge density, small hysteresis and nearly zero flat band voltage.