Microwave Plasma Treatment for High-k Film Nucleation
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Solution Overview
Problem
High-mobility channel semiconductor devices face degradation due to poor oxide and interface quality, and existing high-k dielectric materials like HfO2 struggle with scaling equivalent oxide thickness, necessitating improved nucleation and electrical mobility techniques.
Innovation Solution
The method involves using microwave plasma treatment to form a modified interface layer on a substrate by exposing it to plasma excited species from a hydrogen and noble gas mixture, followed by atomic layer deposition of a high-k film, which enhances nucleation rate and electrical mobility, and reduces interface layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the equivalent oxide thickness is scaled down to continue device scaling, then device performance is improved, but the interface layer thickness must be reduced which degrades interface quality and nucleation rate
Solution Approach 1:
The patent changes the physical and chemical parameters of the interface layer through microwave plasma treatment. The plasma exposure modifies the interface layer's surface properties, creating a more reactive surface that enhances nucleation rate without requiring thickness reduction. This parameter change allows maintaining interface quality while enabling continued scaling of equivalent oxide thickness.
Solution Approach 2:
The microwave plasma treatment is applied as a preliminary step before high-k dielectric deposition. This preliminary action modifies the interface layer in advance, preparing it with enhanced nucleation properties and improved electrical characteristics. By performing this preparation beforehand, the subsequent deposition process achieves better film quality and higher nucleation rates without compromising interface integrity during scaling.
2Productivity
If conventional interface layers are used with scaled thickness, then EOT scaling is achieved, but electrical mobility degrades due to poor interface quality
Solution Approach 1:
The microwave plasma treatment changes the electrical and physical parameters of the interface layer. The plasma exposure creates a modified interface layer with improved electrical mobility characteristics while maintaining the scaled thickness required for EOT scaling. This parameter modification resolves the trade-off between thickness scaling and electrical performance.
Solution Approach 2:
The modified interface layer acts as an intermediary between the substrate and the high-k dielectric layer. The microwave plasma treatment creates this intermediate structure with optimized properties that mediate between the conflicting requirements of thin thickness for scaling and high quality for electrical mobility. The modified interface layer transfers and enhances the beneficial properties to the overlying high-k film.
3Ease of manufacture
If traditional deposition methods are used on conventional interface layers, then manufacturing process is simple, but high-k film nucleation rate is insufficient
Solution Approach 1:
The microwave plasma treatment is introduced as a preliminary step before the standard ALD deposition process. This preliminary plasma exposure modifies the interface layer to create a more nucleation-friendly surface, thereby enhancing the nucleation rate of the high-k film without complicating the subsequent deposition process. The rest of the manufacturing流程 remains simple and conventional.
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 results in improved nucleation rates and superior material properties for high-k films, enabling advanced semiconductor devices with increased manufacturing throughput and enhanced performance.
Implementation Method 1
forming plasma excited species from the process gas by a microwave plasma source
Implementation Method 2
depositing a high dielectric constant (high-k) film by atomic layer deposition (ALD) on the modified interface layer
Data Source
AI summary
A method for forming a semiconductor device is provided in several embodiments. According to one embodiment, the method includes providing a substrate in a process chamber, flowing a process gas consisting of hydrogen (H2) and optionally a noble gas into the process chamber, forming plasma excited species from the process gas by a microwave plasma source. The method further includes exposing an interface layer on the substrate to the plasma excited species to form a modified interface layer, and depositing a high dielectric constant (high-k) film by atomic layer deposition (ALD) on the modified interface layer. In some embodiments, the modified interface layer has higher electrical mobility than the interface layer, and the high-k film nucleates at a higher rate on the modified interface layer rate than on the interface layer.