Transistor structure

A transistor structure, comprising:

• a source region and a drain region disposed in a substrate and extend along a first direction;
• and
• a polysilicon layer, disposed over the substrate and extending along a second direction perpendicular to the first direction, wherein the polysilicon layer comprises a first edge region, a channel region and a second edge region, the first edge region, the channel region and the second edge region formed as a gate region between the source region and the drain region in a plane view,
• wherein the polysilicon layer comprises at least a first opening pattern at the first edge region and at least a second opening pattern at the second edge region, the first opening pattern has a first portion overlapping with the gate region, and the second opening pattern has a second portion overlapping with the gate region,
• wherein a portion of the substrate right under the source region, the drain region and the gate region is a single conductivity type,
• wherein a cross-sectional structure taken along the first direction of the first edge region and/or the second edge region comprises:
• the source region and the drain region disposed in the substrate;
• a gate insulation layer disposed on the substrate and between the source region and the drain region in the plane view;
• and
• the polysilicon layer disposed on the gate insulation layer, wherein the polysilicon layer has an opening between the source region and the drain region in the plane view exposing the gate insulation layer.