Silicon Dioxide Thin Films by ALD with Disilane
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Solution Overview
Problem
Conventional methods for depositing silicon dioxide thin films, such as CVD, face challenges with low growth rates and inadequate conformality, making them economically and technically unsuitable for applications requiring good step coverage and filling capabilities, such as shallow trench isolation and field emission displays.
Innovation Solution
The use of atomic layer deposition (ALD) with disilane compounds like hexakis(ethylamino)disilane as a silicon source and ozone as a reactive oxygen source, allowing for sequential and self-saturating surface reactions to form silicon oxide thin films with improved growth rates and conformality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional CVD methods are used to deposit silicon dioxide thin films, then the deposition process is simple and fast, but the step coverage and conformality are insufficient
Solution Approach 1:
The deposition process is segmented into sequential half-cycles: first introducing the silicon precursor (TEOS) for a controlled time period, then introducing the oxygen source (ozone) in a separate half-cycle. This segmentation of the deposition process into distinct, sequential steps enables precise control over film growth and achieves superior step coverage and conformality compared to conventional simultaneous CVD methods.
2Productivity
If ALD processes are used with traditional precursors, then good conformality is achieved, but the growth rate per cycle is low making processing economically non-viable
Solution Approach 1:
The invention changes the chemical parameters by selecting TEOS as the silicon precursor and ozone as the oxygen source, with specific control over exposure times and temperatures. By optimizing these parameters—particularly using TEOS which provides higher reactivity and faster decomposition rates—the growth rate per cycle is significantly enhanced while maintaining the conformal deposition characteristics of ALD, making the process economically viable.
3Manufacturing precision
If conventional CVD methods are used, then the deposition speed is fast, but the film uniformity and conformality are inadequate
Solution Approach 1:
The deposition employs periodic, alternating introduction of precursor and reactant gases in controlled half-cycles. The silicon precursor (TEOS) is introduced first for a specific duration, followed by purging, then the oxygen source (ozone) is introduced in a subsequent half-cycle. This periodic action ensures complete surface coverage and uniform film growth while maintaining efficient deposition rates, achieving both high film uniformity and reasonable deposition speed.
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 higher growth rates and uniformity of silicon dioxide films, addressing the limitations of conventional CVD methods by providing films with high step coverage and electrical homogeneity, suitable for advanced semiconductor and display technologies.
Implementation Method 1
contacting a substrate in a reaction space with a first reactant that includes a silicon source chemical... and a second reactant comprising an oxygen source, thereby forming the silicon oxide thin film on the substrate
Implementation Method 2
a second reactant comprising an oxygen source... forming the silicon oxide thin film
Implementation Method 3
atomic layer deposition (ALD)... based on sequential, self-saturated surface reactions
Implementation Method 4
sequential and self-saturating surface reactions to form silicon oxide thin films
Data Source
AI summary
Methods are provided for depositing silicon dioxide containing thin films on a substrate by atomic layer deposition ALD. By using disilane compounds as the silicon source, good deposition rates and uniformity are obtained.