Polycrystalline Silicon Channel Doping for Low-Hysteresis Displays

The patent applies local quality by doping different types of impurities at different locations within the channel region. Specifically, a first type of impurity (e.g., phosphorus) is doped into a first region of the channel, while a second type of impurity (e.g., boron) is doped into a second region of the channel. This spatial differentiation of impurity types allows each region to contribute differently to the overall transistor performance, reducing hysteresis and image retention effects while maintaining manufacturing feasibility through targeted doping processes.

The patent implements local quality by creating distinct impurity regions within the channel. A first region contains a first type of impurity (such as phosphorus) that provides beneficial doping effects, while a second region contains a second type of impurity (such as boron) that counteracts hysteresis and image retention. This localized differentiation allows the channel to simultaneously achieve improved transistor characteristics and reduced harmful effects that would result from uniform impurity doping.

The patent applies segmentation by dividing the channel region into multiple distinct regions (first region and second region), each receiving a specific type of impurity doping. This segmentation strategy works effectively with polycrystalline silicon because the discrete region definition allows for controlled impurity distribution even in the polycrystalline structure. The channel is thus segmented both spatially and chemically, enabling precise control over the electrical characteristics of different channel portions while maintaining the manufacturing advantages of polycrystalline silicon.