Thin Film Transistor Metal Barrier Layer Etch Protection
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Solution Overview
Problem
The existing dry etching process for forming source and drain in top-gate thin film transistors is challenging due to endpoint control issues and active layer corrosion, leading to reduced contact area and increased contact resistance, which affects the electrical properties of the transistor.
Innovation Solution
A thin film transistor design incorporating a metal barrier layer to protect the active layer during etching and enhance electrical connection between the source, drain, and active layer, with a through hole in the inner layer dielectric layer exposing the metal barrier layer, allowing for increased contact area and improved conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a dry etching process is adopted to etch through the inner layer dielectric layer, then the source and drain can be formed, but the active layer in the channel region is easily corroded and the endpoint is not easy to control
Solution Approach 1:
A metal barrier layer is introduced as an intermediary protective layer between the inner layer dielectric layer and the active layer. This barrier layer serves as a mediator that prevents the etching process from directly contacting and corroding the active layer, while still allowing the etch to proceed through the dielectric layer to form the necessary holes for source and drain contact.
Solution Approach 2:
The metal barrier layer is deposited on the active layer before the etching process begins. This preliminary protective action ensures that when the inner layer dielectric layer is subsequently etched, the active layer is already protected and cannot be corroded by the etching process.
2Ease of manufacture
If the inner layer dielectric layer is etched through to form deep holes, then the source and drain can contact the active layer, but the contact area is reduced and contact resistance increases
Solution Approach 1:
The metal barrier layer acts as an intermediary conductive layer that extends the contact area between the source/drain and the active layer. By depositing this barrier layer before etching, it becomes part of the contact structure, effectively increasing the contact area and reducing contact resistance while still allowing proper contact formation.
3Manufacturing precision
If a metal barrier layer is added to protect the active layer, then active layer corrosion is prevented and contact area is increased, but the device structure becomes more complex
Solution Approach 1:
The metal barrier layer serves multiple functions simultaneously: it protects the active layer from etching corrosion, increases the contact area between source/drain and active layer, provides a conductive path, and serves as an etch stop layer. By combining multiple functions into a single layer, the overall device complexity is minimized while achieving multiple protective and functional goals.
Data Source
AI summary
The present disclosure provides a thin film transistor, a manufacturing method of the thin film transistor and a display device, configured to improve electrical property of the thin film transistor. The thin film transistor includes: an active layer, including a source and drain contact region and a channel region; a metal barrier layer, covering the source and drain contact region; a first gate insulating layer, at least covering the channel region and exposing the metal barrier layer; a gate, on the first gate insulating layer and covering the channel region; an inner layer dielectric layer, on the gate and having a through hole exposing the metal barrier layer; and a source and drain, on the inner layer dielectric layer and in contact with the metal barrier layer through the through hole.