Back-channel-oxidized a-Si:H thin-film transistors

Abstract

We have developed a back-channel-oxidized thin-film transistor (TFT) structure which does not require the conventional etching of the n+-a-Si:H layer from the channel region. Key processes in the fabrication of this structure are the deposition of a very thin (less than 10 nm) n+-a-Si:H layer with low resistivity (∼50 Ω cm), and an oxygen plasma treatment to change the n+-a-Si:H layer above the channel region into dielectric oxide. With a thin (∼50 nm) a-Si:H layer, the back-channel-oxidized TFT structure makes it possible to obtain much better “ON” characteristics than are obtained with conventional channel-etched TFTs. To gain insight into the underlying physical mechanism we investigated the back-channel electrical characteristics of both types of TFTs as a function of temperature, and found that back-channel-oxidized TFTs had much better back-channel characteristics than channel-etched TFTs, which is due to a lower density of back-channel interface states.

Temperature-Dependent Transfer Characteristics of Amorphous InGaZnO4 Thin-Film Transistors

“…11) The thickness of the a-Si:H layer is 30 nm. The structure of the a-Si:H TFT is a back-channel-etched type without an ordinary SiN x passivation layer.…”

P‐2: The Photosensitive Organic Passivation Thin Film Transistors with High Anti‐Water Absorption Ability

“…Before the photosensitive organic passivation is spun on, the back channel of TFT is dealt with the oxygen plasma treatment, and a thin oxide layer of about 3nm to 5nm is formed in the back channel interface. The thin oxide layer can be used for the anti-water absorption layer of the active region [2,3]. The ITO film is then deposited and patterned as the pixel electrodes on the passivation layer.…”

Improved performance of amorphous silicon thin film transistors by cyanide treatment

“…This would also help to improve the switching behavior of the transistor. It is noteworthy here that Takechi et al 22 observed the similar drastic improvement in TFT performance by modulating the channel chemistry through the oxygen plasma-induced oxidation of n ϩ amorphous silicon above the channel region into dielectric oxide. The higher performance of such back channel oxidized a-Si:H TFTs was reported to be due to lower density of back-channel defect states.…”