AVS 62nd International Symposium & Exhibition
    Electronic Materials and Processing Monday Sessions
       Session EM+AS+SS-MoA

Invited Paper EM+AS+SS-MoA7
Bandgap Engineering and Application of SiZnSnO Amorphous Oxide Semiconductor

Monday, October 19, 2015, 4:20 pm, Room 211A

Session: MIM Diodes, Functional Oxides, and TFTs
Presenter: Sang-Yeol Lee, Cheongju University, Republic of Korea
Correspondent: Click to Email
The band gap of the amorphous SiZnSnO (SZTO) semiconductor has been controlled by bandgap engineering using Si ratio. The addition of small amount of Si in SZTO channel layer can change the position of Fermi level in band gap. By investigating the ultraviolet photoelectron spectroscopy (UPS) characteristics, it is verified that Si atoms can modify the Fermi energy level of SZTO thin films. Carrier generation originated from the oxygen vacancy could modify the Fermi level in the band gap of oxide thin films since Si could be an oxygen vacancy suppressor. This is also related with the origin of defect state which was observed to be involved with the creation of oxygen vacancies. Since it is not so easy to derive directly the change of the Fermi energy level in the energy band gap of amorphous oxide semiconductor, no report of the relation between the Fermi energy level in the energy band gap of oxide semiconductor and the device stability of oxide thin film transistors has been reported. We derive directly band gap and Fermi energy level by using the ultraviolet photoelectron spectroscopy (UPS) characteristics, Kelvin probe (KP) and electron energy loss spectroscopy (EELS). The instability mechanism of amorphous oxide thin film transistors based on the band parameter of oxide semiconductor will be discussed and applied to display applications.