Abstract: In a circuit including at least one thin film transistor formed on an insulating substrate, a region 105 to which metal elements that promote crystallinity are added is disposed apart from a semiconductor island region 101 that forms the thin film transistor by a distance y, has a width w, and extends longitudinally over an end portion of the semiconductor island region 101 by a distance x. Also, in a TFT manufactured in a region which is not interposed between the nickel added regions, another nickel added region is disposed (resultantly, which is interposed between two nickel added regions). Further, all the intervals between the respective nickel added regions are preferably identified with each other. Thus, a thin film transistor circuit being capable of a high speed operation (in general, some tens of Mhz and more) is formed. In particular, correcting the difference of crystal growths, using a crystalline silicon film added with nickel, TFTs with uniform characteristics can be provided.

Abstract: Concentration of metal element which promotes crystallization of silicon and which exists within a crystal silicon film obtained by utilizing the metal element is reduced. A first heat treatment for crystallization is implemented after introducing nickel element to an amorphous silicon film 103. Then, after obtaining the crystal silicon film, another heat treatment is implemented within an oxidizing atmosphere at a temperature higher than that of the previous heat treatment. At this time, HCl or the like is added to the atmosphere. A thermal oxide film 106 is formed in this step. At this time, gettering of the nickel element into the thermal oxide film 106 takes place. Next, the thermal oxide film 106 is removed. Thereby, a crystal silicon film 107 having low concentration of the metal element and a high crystallinity can be obtained.

Abstract: In a peripheral driver circuit of a liquid crystal electro-optical device is comprised of a shift register circuit arranged by a plurality of registers, and a circuit for supplying power to each register. When an input signal is entered into an nth register, a supply of power to at least a portion of registers other than the nth register is stopped. The shift register circuit is constructed of a P-channel type TFT and a resistor. The circuit for supplying the power controls the supply of power to the shift register by using the output of the shift register circuit. This circuit for supplying the power is arranged by a P-channel type TFT and a resistor. The consumption power of the circuit for supplying the power is equal to and lower than that of the shift register circuit.

Abstract: Concentration of metal element which promotes crystallization of silicon and which exists within a crystal silicon film obtained by utilizing the metal element is reduced. A first heat treatment for crystallization is implemented after introducing nickel to an amorphous silicon film. Then, after obtaining the crystal silicon film, another heat treatment is implemented within an oxidizing atmosphere at a temperature higher than that of the previous heat treatment. A thermal oxide film is formed in this step. At this time, gettering of the nickel element into the thermal oxide film takes place. Then, the thermal oxide film is removed. Thereby, a crystal silicon film having low concentration of the metal element and a high crystalinity can be obtained.

Abstract: By forming a gate electrode, a source electrode and a drain electrode so as to assume concentric circles on an active layer made of, for instance, a crystalline silicon thin film, it is prevented that an edge of the active layer is located on a line connecting the source and drain electrodes. This configuration prevents the source and drain electrodes from being short-circuited by the gate electrode, resulting in reduction of a leak current. Specifically, a channel region may surround one the source and drain region while the other of the source and drain region surrounds the channel region. Alternatively, the gate electrode may surround one the source and drain region while the other of the source and drain region surrounds the channel region.