Fujitsu Corporation

Ken-ichi Oki

Ken-ichi Yanai

Tsutomu Tanaka

Yutaka Takizawa

Koji Ohgata

Tamotsu Wada

Masahiro Okabe

Takuya Hirano

Michiko Takei

Kazuhiro Takahara

Yasuyoshi Mishima

Satoru Kawai

Tatsuya Kakehi

Kohji Ohgata

Norihisa Matsumoto

Mari Hodate

Ken-iti Yanai

To form a contact layer on source and drain electrodes of a stagger-type TFT, a conductive material is selectively sticked to the surface of the source and drain electrodes and a contact layer is selectively deposited by using the conductive material as growth species to form an active semiconductor layer on the contact layer. For an inverted-stagger-type TFT, a conductive material is selectively deposited on the surface of a contact layer to use the selectively deposited conductive material as source and drain electrodes so that patterning is unnecessary. To selectively deposit a contact layer of a TFT by alternately repeating etching and deposition, the temperature for the etching is set to 200&deg; C. or lower. A contaminated layer on the surface of a semiconductor film serving as an active semiconductor layer and contact layer of a TFT is removed by plasma at the temperature of 200&deg; C. or lower. For a stagger-type thin-film transistor, the hydrogen or halogen content of an insulating film serving as the substrate of source and drain electrodes is increased. For an inverted-stagger thin-film transistor, the hydrogen or halogen content of an insulating film serving as a channel protective film is increased. Thus, the etching rate of the surfaces of these insulating films by plasma increases.

Method for fabricating thin-film transistor

A thin film transistor matrix device comprises an insulating substrate, a plurality of picture element electrodes arranged in a matrix on the insulating substrate, source electrodes connected to the respective picture element electrodes, drain electrodes opposed to the respective source electrodes, operational semiconductor layers sandwiched by the source electrodes and the drain electrodes, and gate electrodes formed on the operational semiconductor layers through gate insulating films, each gate electrode being narrowed with respect to the associated gate insulating film so that side walls of the gate electrode forms a step with respect to side walls of the associated gate insulating film which is a substrate of the gate electrode. The gate electrode is made narrower with respect to the gate insulating film to form a step between the side walls of the gate electrode with respect to those of the gate insulating film, whereby leak currents from the source electrode or the drain electrode to the gate electrode along the mesa side surfaces of the TFT can be simply suppressed. Accordingly a TFT matrix device having little wasteful current consumption can be realized.

Thin film transistor matrix device

Thin film transistor matrix device and method for fabricating the same

To form a contact layer on source and drain electrodes of a stagger-type TFT, a conductive material is selectively sticked to the surface of the source and drain electrodes and a contact layer is selectively deposited by using the conductive material as growth species to form an active semiconductor layer on the contact layer. For an inverted-stagger-type TFT, a conductive material is selectively deposited on the surface of a contact layer to use the selectively deposited conductive material as source and drain electrodes so that patterning is unnecessary. To selectively deposit a contact layer of a TFT by alternately repeating etching and deposition, the temperature for the etching is set to 200.degree. C. or lower. A contaminated layer on the surface of a semiconductor film serving as an active semiconductor layer and contact layer of a TFT is removed by plasma at the temperature of 200.degree. C. or lower. For a stagger-type thin-film transistor, the hydrogen or halogen content of an insulating film serving as the substrate of source and drain electrodes is increased. For an inverted-stagger thin-film transistor, the hydrogen or halogen content of an insulating film serving as a channel protective film is increased. Thus, the etching rate of the surfaces of these insulating films by plasma increases.

A thin film transistor matrix device is fabricated by forming a transparent conductor film and a metal film on an insulating substrate in this order. The metal film and the transparent conductor film are together patterned to form picture element electrodes, and drain bus lines or gate bus lines. Source electrodes and drain electrodes may also be formed from the transparent conductor film and metal film. A semiconductor layer, an insulating film and a conductor film may be formed on the entire surface in this order. In this case, the conductor film, the insulator film and the semiconductor layer are patterned to form an active layer from the semiconductor layer, gate insulating films from the insulating film, and gate electrodes and gate bus lines from the conductor film. By patterning the conductor film, the insulating film and the semiconductor layer, the metal film of the picture element electrodes and drain bus lines is exposed. Alternatively, the metal film may be patterned with the semiconductor layer, insulating film and conductor film to expose the transparent conductor film. A current is applied to the drain bus lines or gate bus lines in an electrolyte solution to selectively form a film on the drain bus lines or gate bus lines. The film may be a protecting film serving as a mask to allow the metal film on the picture element electrodes to be etched.

Method for fabricating a thin film transistor matrix device

A method of manufacturing a semiconductor device according to the present invention includes a process of introducing impurities into a semiconductor layer with a gate electrode and a resist film as a mask after a resist film is formed on the top and the side of the gate electrode by soaking the gate electrode on a semiconductor layer in an electrolyte containing resist and applying voltage to the gate electrode.

Method of manufacturing thin film transistors in a liquid crystal display

Method for fabricating a thin-film transistor

In an active matrix-type display device, two pixel electrodes of cells neighboring in the direction of scan bus lines are connected to the same data bus line, and these two cells are independently controlled by the time division technique. When an address pulse is applied to the scan bus line for accessing each cell of the pixel rows, a compensation pulse is applied to the scan bus line arranged on the other side of the pixel row.

Active matrix-type display device having a reduced number of data bus

An active matrix display device of an improved and simplified configuration and a driving method for the same are disclosed. The display device according to the present invention is characterized in that data bus lines and scan bus lines are separately formed on first and second transparent substrates respectively and the drain electrode of each TFT on the second substrate is connected to the scan bus line to be addressed next. This configuration eliminates earth bus lines of the prior art. This arrangement has effects of simplifying a bus line design and obtaining a higher yield and an increased opening rate for each display element. In order to drive the above device, an address pulse having a stepped waveform is used. Each address pulse has Vgon, Vgc, and Vgoff levels, and a width of two horizontal scan time. The first step of address pulse Vgc corresponds to the address time of the adjacent scan bus line to be scanned previously; and the second step Vgon corresponds to the address time for the TFT to be scanned. The present invention discloses a voltage relation for waveforms of the address pulse and data pulse in order to obtain a high quality display.

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Kawasaki, Japan

Ken-ichi Oki