Cuprous Oxide P-Type Transistors via Low-Temperature Plasma Oxidation
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Solution Overview
Problem
The semiconductor industry faces challenges in forming high-quality cuprous oxide layers for BEOL levels due to high process temperatures required in conventional techniques, which can lead to diffusion of contaminants and reduced device performance, and existing oxide semiconductor materials have low hole mobility, making them unsuitable for p-type transistors.
Innovation Solution
A method involving plasma-enhanced oxidation between a crystalline copper layer and an inert dielectric layer, such as aluminum oxide, to form a crystalline cuprous oxide layer with a (111) crystal plane at a controlled temperature between 350° C and 450° C, which is then transferred to a workpiece for further processing into transistors, allowing for the formation of p-type transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional high-temperature oxidation techniques are used to form cuprous oxide layers, then complete oxidation and high-quality material formation are achieved, but process temperature becomes too high causing diffusion of contaminants and reduced device performance
Solution Approach 1:
The patent changes the oxidation parameters by using plasma-enhanced oxidation instead of conventional thermal oxidation, enabling the formation of high-quality cuprous oxide layers at lower temperatures (350-450°C) while maintaining complete oxidation and material quality
Solution Approach 2:
The patent introduces an inert dielectric layer as an intermediary between the copper layer and the oxidation environment, controlling the oxidation process to form cuprous oxide at reduced temperatures while preventing over-oxidation and contaminant diffusion
2Temperature
If amorphous silicon transistors are used at low process temperatures, then thermal budget constraints are met, but carrier mobility is insufficient for BEOL power gate or I/O devices
Solution Approach 1:
The patent changes the material phase from amorphous to crystalline, forming crystalline cuprous oxide that provides high carrier mobility suitable for BEOL applications while maintaining compatibility with low thermal budget processing
Solution Approach 2:
The patent uses a composite structure involving crystalline copper layer, inert dielectric layer, and plasma treatment to achieve crystalline cuprous oxide formation with high mobility at low temperatures
3Ease of manufacture
If existing oxide semiconductor materials are used, then processing is simplified, but hole mobility is low making them unsuitable for p-type transistors
Solution Approach 1:
The patent changes the material composition from conventional oxide semiconductors to cuprous oxide, which inherently provides high hole mobility suitable for p-type transistors while maintaining ease of fabrication through the described oxidation process
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
This approach enables the formation of high-quality crystalline cuprous oxide layers at lower temperatures, meeting thermal budget constraints and enabling the fabrication of p-type transistors with improved mobility, addressing the limitations of conventional techniques.
Implementation Method 1
A method involving plasma-enhanced oxidation between a crystalline copper layer and an inert dielectric layer, such as aluminum oxide, to form a crystalline cuprous oxide layer
Data Source
AI summary
Structures and methods of forming the same are provided. A structure according to the present disclosure includes an interconnect structure, an aluminum oxide layer over the interconnect structure, and a transistor formed over the aluminum oxide layer. The transistor includes cuprous oxide.