Horizontal Gate-All-Around Oxide Formation Using Plasma Oxidation
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Solution Overview
Problem
Conventional I/O oxide processes for forming horizontal gate-all-around devices result in poor quality native oxide, low-density oxide deposition, and increased complexity and cost due to the need for additional post-treatment to densify the ALD film.
Innovation Solution
The method involves pre-cleaning a plurality of nanosheet channel layers, forming a conformal sacrificial epitaxial layer, and then oxidizing this layer using plasma to form a high-quality silicon oxide layer on the nanosheets, thereby improving the electrostatic coupling and reducing parasitic capacitance and off-state leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional I/O oxide processes are used, then oxide deposition is achieved, but the oxide quality is poor and density is low
Solution Approach 1:
The patent applies preliminary action by performing a pre-clean step on the nanosheet channel layers before oxide deposition. This pre-clean removes contaminants and prepares the surface, enabling subsequent formation of high-quality, high-density oxide without requiring post-treatment densification steps.
Solution Approach 2:
The patent changes the oxidation method parameter from conventional ALD (Atomic Layer Deposition) to plasma oxidation. This parameter change transforms the oxidation process to produce high-density oxide directly, eliminating the need for post-deposition densification while achieving superior oxide quality.
2Manufacturing precision
If ALD oxide deposition is used, then oxide layer is formed, but additional post treatment is required to densify the film
Solution Approach 1:
The patent extracts and removes the post-treatment densification step from the conventional ALD oxide formation process. By using plasma oxidation instead of ALD, the method directly produces dense oxide without requiring the additional post-treatment step, thereby simplifying the overall process.
Solution Approach 2:
The patent changes the deposition method from ALD to plasma oxidation. This parameter change fundamentally alters the deposition mechanism to produce dense oxide in-situ, eliminating the need for subsequent densification treatments and reducing process complexity.
3Reliability
If conventional oxide formation is used, then oxide layer is deposited, but electrostatic control is poor and parasitic capacitance increases
Solution Approach 1:
The patent applies preliminary action by pre-cleaning the nanosheet surfaces before oxide formation. This ensures a clean interface that enables optimal electrostatic coupling between the gate and channel, reducing parasitic capacitance and improving electrostatic control of the device.
Solution Approach 2:
The patent changes the oxide formation method to plasma oxidation, which produces high-quality oxide with superior dielectric properties. This parameter change improves electrostatic control by reducing interface states and minimizing parasitic capacitance, leading to better device performance.
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 I/O oxides with improved electrostatic control, reducing negative effects such as parasitic capacitance and off-state leakage, while also simplifying the manufacturing process and reducing costs.
Implementation Method 1
oxidizing the conformal sacrificial epitaxial silicon layer using a plasma to form a silicon oxide layer on the nanosheet
Data Source
AI summary
Horizontal gate-all-around devices and methods of manufacturing same are described. The hGAA devices comprise an oxide layer and a semiconductor material layer between source regions and drain regions of the device. The method includes growing a conformal epitaxial layer on a nanosheet channel layer, followed by radical plasma oxidation (RPO) to oxidize the conformal epitaxial layer. An alternative method includes growing a conformal epitaxial layer on a nanosheet channel layer, followed by a surface treatment, and then radical plasma oxidation (RPO) to oxidize the conformal epitaxial layer.