| 摘要 |
PURPOSE:To make an operation speed of a driving TFT faster than that of a switching TFT without generating a ununiformity of a thin film and reducing the image quality, by making a second semiconductor thin film thicker than a first one which is formed on the same substrate where the second semiconductor thin film is formed. CONSTITUTION:About 30,000 pieces of switching TFTs (thin film transistors) 20 are arranged in the form of a matrix in an area 2 on a glass substrate 1 and about 3,000 pieces driving TFT's 30 are arranged in an area 3. Each of the TFTs 20 is a multi-crystal silicon film 200 formed on the substrate 1, having a gate electrode 5 on it with a gate film 4 put between. In a like manner, each of the TFTs 30 is a multi-crystal silicon film 300 formed on the substrate 1, having a gate electrode 5 on it with a gate film 4 put between. Each TFT 20 and 30 also have source areas 21 and 31, drain areas 22 and 32 and channel areas 23 and 33 respectively. By making the film 300 thicker than the film 200, the operation speed of the TFT 30 can be faster than that of the TFT 20 without injuring the uniformity of the characteristics of the TFTs 30 and without increasing the reverse leak current of the TFTs 20. |
