The present application relates to an active switch, a manufacturing method thereof and a display device. The manufacturing method of the active switch includes: sequentially forming a gate electrode, a gate insulating layer, an active layer, a semiconductor composite layer and a source electrode and a drain electrode on a substrate. The semiconductor composite layer includes a first N-type heavily doped amorphous silicon layer, a first N-type lightly doped amorphous silicon layer, a second N-type heavily doped amorphous silicon layer and a second N-type lightly doped amorphous silicon layer which are sequentially stacked, where the ion doping concentration of the first N-type heavily doped amorphous silicon layer is lower than that of the second N-type heavily doped amorphous silicon layer, and the ion doping concentration of the first N-type lightly doped amorphous silicon layer is higher than that of the second N-type lightly doped amorphous silicon layer.

A semiconductor device with favorable electrical characteristics is provided. A highly reliable semiconductor device is provided. The semiconductor device includes a semiconductor layer, a first insulating layer over the semiconductor layer, and a conductive layer over the first insulating layer. The semiconductor layer includes a first region, a pair of second regions, a pair of third regions, and a pair of fourth regions. The second regions sandwich the first region, the third regions sandwich the first region and the second regions, and the fourth regions sandwich the first region, the second regions, and the third regions. The first region includes a region overlapping with the first insulating layer and the conductive layer, the second regions and the third regions each include a region overlapping with the first insulating layer and not overlapping with the conductive layer, and the fourth regions overlap with neither the first insulating layer nor the conductive layer. A thickness of the first insulating layer in regions overlapping with the second regions is substantially equal to a thickness of the first insulating layer in a region overlapping with the first region. A thickness of the first insulating layer in regions overlapping with the third regions is smaller than the thickness of the first insulating layer in the regions overlapping with the second regions.

To provide a method for driving a semiconductor device, by which influence of variation in threshold voltage and mobility of transistors can be reduced. The semiconductor device includes an n-channel transistor, a switch for controlling electrical connection between a gate and a first terminal of the transistor, a capacitor electrically connected between the gate and a second terminal of the transistor, and a display element. The method has a first period for holding the sum of a voltage corresponding to the threshold voltage of the transistor and an image signal voltage in the capacitor; a second period for turning on the switch so that electric charge held in the capacitor in accordance with the sum of the image signal voltage and the threshold voltage is discharged through the transistor; and a third period for supplying a current to the display element through the transistor after the second period.

The present application relates to an active switch, a manufacturing method thereof and a display device. The manufacturing method of the active switch includes: sequentially forming a gate electrode, a gate insulating layer, an active layer, a semiconductor composite layer and a source electrode and a drain electrode on a substrate. The semiconductor composite layer includes a first N-type heavily doped amorphous silicon layer, a first N-type lightly doped amorphous silicon layer, a second N-type heavily doped amorphous silicon layer and a second N-type lightly doped amorphous silicon layer which are sequentially stacked, where the ion doping concentration of the first N-type heavily doped amorphous silicon layer is lower than that of the second N-type heavily doped amorphous silicon layer, and the ion doping concentration of the first N-type lightly doped amorphous silicon layer is higher than that of the second N-type lightly doped amorphous silicon layer.

A thin film transistor, a method for fabricating the same, an array substrate, a display panel, and a display device are provided. The thin film transistor includes a substrate, and an active layer on the substrate, wherein the active layer includes a poly-silicon layer and has a channel region and two electrode connection regions respectively on two sides of the channel region, and the channel region includes a plurality of lightly drain doping segments, which are spaced apart along from one of the electrode connection regions to the other electrode connection region, and channel segments located between the lightly drain doping segments.

A thin film transistor includes an active layer, a gate electrode spaced apart from and partially overlapped with the active layer, and a gate insulating film between the active layer and the gate electrode, wherein the active layer includes a channel portion overlapped with the gate electrode, a conductorization portion which is not overlapped with the gate electrode, and a gradient portion between the channel portion and the conductorization portion and not overlapped with the gate electrode, the conductorization portion and the gradient portion of the active layer are doped with a dopant, the gate insulating film covers an upper surface of the active layer facing the gate electrode during doping of the active layer, and in the gradient portion, a concentration of the dopant increases along a direction from the channel portion toward the conductorization portion. A display device may also include the thin film transistor.

To provide a method for driving a semiconductor device, by which influence of variation in threshold voltage and mobility of transistors can be reduced. The semiconductor device includes an n-channel transistor, a switch for controlling electrical connection between a gate and a first terminal of the transistor, a capacitor electrically connected between the gate and a second terminal of the transistor, and a display element. The method has a first period for holding the sum of a voltage corresponding to the threshold voltage of the transistor and an image signal voltage in the capacitor; a second period for turning on the switch so that electric charge held in the capacitor in accordance with the sum of the image signal voltage and the threshold voltage is discharged through the transistor; and a third period for supplying a current to the display element through the transistor after the second period.

According to one embodiment, in a first concentration of an impurity element contained in a first impurity region, a second concentration of the impurity element contained in a second impurity region, a third concentration of the impurity element contained in a third impurity region, and a fourth concentration of the impurity element contained in a high-concentration impurity region, the third concentration is equal to the fourth concentration, the third concentration is higher than the first concentration, and the first concentration is higher than the second concentration.

A thin film transistor includes an active layer, a gate electrode spaced apart from and partially overlapped with the active layer, and a gate insulating film between the active layer and the gate electrode, wherein the active layer includes a channel portion overlapped with the gate electrode, a conductorization portion which is not overlapped with the gate electrode, and a gradient portion between the channel portion and the conductorization portion and not overlapped with the gate electrode, the conductorization portion and the gradient portion of the active layer are doped with a dopant, the gate insulating film covers an upper surface of the active layer facing the gate electrode during doping of the active layer, and in the gradient portion, a concentration of the dopant increases along a direction from the channel portion toward the conductorization portion. A display device may also include the thin film transistor.

To provide a method for driving a semiconductor device, by which influence of variation in threshold voltage and mobility of transistors can be reduced. The semiconductor device includes an n-channel transistor, a switch for controlling electrical connection between a gate and a first terminal of the transistor, a capacitor electrically connected between the gate and a second terminal of the transistor, and a display element. The method has a first period for holding the sum of a voltage corresponding to the threshold voltage of the transistor and an image signal voltage in the capacitor; a second period for turning on the switch so that electric charge held in the capacitor in accordance with the sum of the image signal voltage and the threshold voltage is discharged through the transistor; and a third period for supplying a current to the display element through the transistor after the second period.