Top-Gate TFT Doping Layout for Lower Contact Resistance
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Solution Overview
Problem
Top-gate thin film transistors (TFTs) suffer from contact resistance issues.
Innovation Solution
A TFT structure is designed with a sheet of doping on the top surface of the TFT channel material, incorporating specific dielectric and metal layers to improve contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If top-gate TFT configuration is used, then low temperature processing is enabled, but contact resistance increases
Solution Approach 1:
The patent applies local quality by creating a doped region specifically at the top surface of the channel layer where contact is needed, while the bulk channel layer remains undoped or lightly doped. This localized doping at the contact interface reduces contact resistance without affecting the overall low-temperature processing advantage of the top-gate configuration.
Solution Approach 2:
The patent implements preliminary action by forming the doped region in the channel layer before final contact formation. This pre-doping step ensures that the contact interface is already optimized for low resistance when contacts are subsequently formed, addressing the contact resistance issue before it becomes a problem in the final device operation.
2Reliability
If doping is applied to reduce contact resistance, then contact resistance decreases, but device complexity increases
Solution Approach 1:
The patent uses parameter changes by modifying the doping concentration and depth specifically in the top surface region of the channel layer. By controlling the doping parameters (concentration, depth, and lateral extent) to create a localized doped region, the patent reduces contact resistance while maintaining a relatively simple overall device structure that is compatible with standard TFT fabrication processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The doping on the top surface of the TFT channel material reduces contact resistance, enhancing the performance of top-gate TFTs.
Implementation Method 1
a second structure adjacent to the first structure, the second structure comprising a second material wherein the second material is doped
Data Source
AI summary
Top-gate thin film transistor (TFTs) structures. Thin film transistors when in the top-gate configuration suffer from contact resistance. An example TFT includes a semiconductor layer doped with one or more dopant elements. A gate dielectric layer is on the semiconductor layer, and a gate electrode is on the gate dielectric layer. The semiconductor layer is doped with the one or more dopant elements beneath the gate dielectric layer. The TFT may further include one or more contacts and/or one or more gate spacers, and the semiconductor layer may further be doped with the one or more dopant elements beneath the contact(s) and/or gate spacer(s).