Electronic Materials Letters , vol. 4, no. 2, pp.45-49, June, 2008

DOI :

Grain Boundary Incorporation of Interstitial Oxygen in Polycrystalline Si Film by Plasma Oxidation and its Effect on Thin Film Transistors

Bo Hyun Kim, Seung Ryul Lee, Kyung Min Ahn, and Byung Tae Ahn^*
Korea Advanced Institute of Science and Technology (KAIST)

Abstract : Inductively coupled plasma (ICP) oxidation has been used for low-temperature gate oxidation to reduce the trap density at the Si/SiO₂ interface in polycrystalline-Si thin film transistors. Through ICP oxidation, it was found that oxygen atoms were incorporated into the Si film as an interstitial oxygen state and they were located predominantly at grain boundaries. The amount of interstitial oxygen, analyzed by energy dispersive x-ray spectroscopy, increased as the ICP oxidation time increased. With the help of the interstitial oxygen at the grain boundaries, the electron mobility of poly-Si thin film transistors was improved, indicating that ICP oxidation enabled grain-boundary passivation in addition to the previously-known trap reduction at the Si/SiO₂ interface state.

Keyword : interstitial oxygen, plasma oxydation, passivation, polycrystalline silicon thin film transistor