| Summary: | 碩士 === 國立交通大學 === 工學院半導體材料與製程設備學程 === 99 === In recent years, as far as the specifications of the flat panel displays are concerned, with the need to scale up the panel size and increase the resolution, the requirements of the array process are becoming more demanding. Take the requirement of the metal line resistance for example, the processes have been improved from the earlier Mo process, Al alloy process, pure Al process used frequently
nowadays, to the coming Cu process, all of these process improvements have been made to solve the problem on the RC load effect faced with while scaling up the panels and increasing the resolution. After solving the problem on the metal line resistance of panels, there still are problems on the parasitic capacity loading effect and the device charging. The main purpose to develop the frequently used Amorphous Silicon devices into Low Temperature Poly Silicon devices is to improve the charging ability of devices, and further, to shrink the device size.
Although Low Temperature Poly Silicon devices can improve the
device performance of Amorphous Silicon devices, the costs of facility
investment are higher and the device uniformity would be subject to
the laser anneal conditions and becomes hard to control, which would
in turn result in the bad device uniformity.
Therefore, a great number of the research institutes and the LCD
makers are investing an enormous amount of money to develop the metal oxide semiconductors. The earlier ZnO devices and later metal oxide semiconductors have been sequentially launched. The biggest problem, however, is that the device stability is not good. Therefore, every manufacturer now is doping various elements into the current aterials in order to improve the device stability.
Currently, one of the most popular materials is IGZO which is
considered as one of the materials that are most likely to replace
Amorphous Silicon. So we also hope to utilize different thermal
anneal conditions and plasma treatment methods to improve the
IGZO device stability, and further, to develop the process flows that
are suitable for the IGZO devices. That is why we are probing into
the IGZO thin film with various thermal anneal parameters and
plasma treatment parameters as follows.
Devices can get a higher operation current after 330oC anneal.
And the IGZO film use the N2O treatment, the devices will get
a better stability. Devices using the N2O surface treatment and
2hr 330oC final anneal, Ion of the devices is about 6.4E-5A, the
mobility of the devices is about 11 cm2/V-s, the Vth shift of
the device is about 2.62V at stress time 2000 seconds in Vgs
50V and Vd=Vs=0V. the Vth shift of the device is about 0.44V
at stress time 2000 seconds in Vgs 5V and Vd 15V and Vs 0V。
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