Element substrate and display device

A display device, comprising:

• an element substrate comprising a substrate and an element layer, wherein the element layer is disposed on the substrate, the element layer comprises a plurality of active elements, the plurality of active elements respectively comprises:
• a gate disposed on the substrate;
• a gate insulating layer disposed on the substrate and overlapping the gate;
• a metal oxide semiconductor layer disposed on the gate insulating layer;
• a source and a drain disposed on the metal oxide semiconductor layer,
• wherein the metal oxide semiconductor layer has a first portion and a second portion, the source and the drain overlap the first portion, the source and the drain do not overlap the second portion, the first portion has a first thickness, the second portion has a second thickness, the first thickness is greater than the second thickness,
• wherein a difference between the first thickness and the second thickness is greater than or equal to 200 Å and less than or equal to 600 Å, and
• wherein the source and the drain respectively comprise a first layer and a second layer, the first layer is disposed between the second layer and the metal oxide semiconductor layer, a material of the first layer comprises titanium nitride, a distance is between an edge of the first layer and an edge of the second layer, and the distance is greater than or equal to 0.1 μm and less than or equal to 0.3 μm;
• an opposing substrate disposed relative to the element substrate;
• and
• a display layer disposed between the element substrate and the opposing substrate.