Bi-layer Semiconducting Oxide Source/Drain for Low Contact Resistance
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Solution Overview
Problem
Oxide semiconductors in thin film transistors exhibit high contact and access resistances due to their wide band gap, which hinders their performance in semiconductor manufacturing.
Innovation Solution
Implementing a bi-layer semiconducting oxide structure in the source and drain regions, combining a semiconducting oxide channel layer with a high mobility oxide layer to reduce contact resistance, where the high mobility oxide material is deposited beneath the contacts and spacers, allowing for lower band gap and higher conductivity, thereby reducing total access resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If oxide semiconductors are used in thin film transistors, then low temperature deposition and native substrate independence are achieved, but high contact and access resistances occur due to wide band gap
Solution Approach 1:
The source/drain region is segmented into two distinct oxide semiconductor layers: a first oxide semiconductor layer with wide band gap for low off-state current, and a second oxide semiconductor layer with narrow band gap for low contact resistance. This segmentation allows each layer to optimize for its specific function, resolving the contradiction between ease of manufacture and reliability.
Solution Approach 2:
Different regions of the semiconductor structure are assigned different material properties: the channel region uses wide band gap oxide for low leakage, while the source/drain contact regions use narrow band gap oxide for high conductivity. This local differentiation of material quality enables simultaneous achievement of low temperature deposition capability and low contact resistance.
Data Source
AI summary
In accordance with disclosed embodiments, there are provided systems, methods, and apparatuses for implementing bi-layer semiconducting oxides in a source/drain for low access and contact resistance of thin film transistors. For instance, there is disclosed in accordance with one embodiment a semiconductor device having therein a substrate; a bi-layer oxides layer formed from a first oxide material and a second oxide material, the first oxide material comprising a semiconducting oxide material and having different material properties from the second oxide material comprising a high mobility oxide material; a channel layer formed atop the substrate, the channel layer formed from the semiconducting oxide material of the bi-layer oxides layer; a high mobility oxide layer formed atop the channel layer, the high conductivity oxide layer formed from the high mobility oxide material of the bi-layer oxides layer; metallic contacts formed atop the high mobility oxide layer; a gate and a gate oxide material formed atop the high mobility oxide layer, the gate oxide material being in direct contact with the high mobility oxide layer; and spacers separating the metallic contacts from the gate and gate oxide material. Other related embodiments are disclosed.