Image display device and method for manufacturing the same

Abstract

Only a region where TFTs constituting a high-performance circuit will be disposed in a precursor semiconductor film PCS on an insulating substrate GLS with an insulating layer UCL serving as an undercoat is irradiated with a first energy beam LSR so as to be poly-crystallized while growing crystal grains laterally. Further a second rapid thermal treatment is performed all over the panel so as to reduce defects in the crystal grains in a region PSI poly-crystallized by the aforementioned energy beam. Thus, a high-quality polycrystalline semiconductor thin film serving as TFTs for a high-performance circuit and having a high on-current, a low threshold value, a low variation and a sharp leading edge characteristic is obtained. Concurrently, the precursor semiconductor layer in the other region is poly-crystallized by the second rapid thermal treatment so as to obtain a low-quality polycrystalline semiconductor thin film serving as pixel circuit TFTs and having a low on-current and properties of a low leak current and a high withstand voltage due to its high resistance. Accordingly, it is possible to form polycrystalline semiconductor TFTs high in driving performance and TFTs having properties of a low leak current and a high withstand voltage concurrently on one and the same insulating substrate.