Amorphous Silicon Oxide Layer Growth for High Aspect Ratio Structures
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Solution Overview
Problem
Conventional methods for forming oxide layers in high aspect ratio semiconductor structures face challenges such as high silicon consumption and low quality due to defects and traps, which affect device reliability.
Innovation Solution
A method involving the formation of an amorphous silicon layer on a substrate followed by a direct plasma oxidation process and a thermal oxidation process to selectively oxidize the amorphous silicon, reducing silicon consumption and enhancing oxide layer quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thermal oxidation growth is used to form an oxide layer, then the oxide layer can be formed, but high silicon consumption occurs and the oxide layer cannot be formed thin in high aspect ratio structures
Solution Approach 1:
An amorphous silicon layer is deposited in advance on the substrate before oxidation. This preliminary silicon layer serves as a controlled source for oxidation, allowing precise thickness control of the resulting oxide layer while preventing excessive silicon consumption from the substrate itself.
Solution Approach 2:
The patent changes the physical state and properties of silicon by converting it to amorphous form through deposition, then controlling its oxidation. This parameter change enables better control over oxidation rate and thickness, particularly in high aspect ratio structures where conventional thermal oxidation fails to produce thin uniform layers.
2Reliability
If oxide layer is formed by deposition, then the oxide layer can be formed, but the quality is low with defects and traps leading to reduced device reliability
Solution Approach 1:
The patent replaces physical vapor deposition or chemical vapor deposition methods with a thermal oxidation process. Thermal oxidation grows the oxide layer in-situ from silicon, eliminating the defects and traps inherent in deposited oxide layers, thereby improving device reliability while maintaining precise thickness control.
3Manufacturing precision
If conventional methods are used to form oxide layer in high aspect ratio structures, then the process is simple, but the oxide layer quality is poor with defects and the structure cannot be properly formed
Solution Approach 1:
The amorphous silicon layer is deposited beforehand as a sacrificial or convertible layer that enables subsequent controlled oxidation. This preliminary step, while adding a process stage, provides the foundation for achieving high quality oxide layers in complex high aspect ratio structures that cannot be achieved with conventional single-step methods.
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 allows for the formation of a high-quality thin oxide layer with reduced silicon consumption and defects, enabling improved device reliability and the capability to tune oxide layer thickness, especially in complex geometries like recessed channel array transistors.
Implementation Method 1
performing a direct oxidation process to selectively oxidize the formed amorphous silicon layer
Implementation Method 2
performing a thermal oxidation process to oxidize the formed amorphous silicon layer
Data Source
AI summary
A method for forming an oxide layer includes forming an interfacial layer on a substrate, forming an amorphous silicon layer on the interfacial layer, performing a direct oxidation process to selectively oxidize the formed amorphous silicon layer, and performing a thermal oxidation process to oxidize the formed amorphous silicon layer.