Radical Oxidation Gate Oxide Sidewall Thickness Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High integration of semiconductor devices leads to challenges in controlling threshold voltage, resulting in increased short channel effects and junction leakage, which complicates achieving lower operating voltages and improved refresh characteristics in memory devices.
Innovation Solution
A method involving radical oxidation to form a uniform oxide film in trenches, followed by nitride film deposition and planarization, and then a dry oxidation process to form a gate oxide film with greater thickness at sidewalls, reducing junction leakage and enhancing refresh characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the threshold voltage is decreased to enable lower operating voltage (1V to 2V), then the operating voltage is reduced, but the short channel effect increases causing Drain Induced Built-in Leakage
Solution Approach 1:
The patent applies different doping concentrations at different locations within the channel region. The channel doping concentration is set to be higher than the substrate doping concentration, creating a locally optimized doping profile that addresses the short channel effect at the channel region while maintaining overall device performance at lower operating voltages.
2Productivity
If high integration is implemented to improve device density, then the integration level is increased, but the threshold voltage control becomes difficult due to short channel effects
Solution Approach 1:
The patent implements a localized doping strategy where the channel region receives a higher doping concentration than the substrate. This local quality enhancement allows high integration to be achieved while maintaining precise threshold voltage control in the critical channel region, preventing short channel effects from degrading manufacturing precision.
Solution Approach 2:
The patent changes the doping concentration parameter specifically in the channel region, setting it higher than the substrate doping concentration. This parameter change enables the device to maintain stable threshold voltage control even under high integration conditions, resolving the contradiction between integration level and manufacturing precision.
3Ease of manufacture
If conventional oxidation processes are used to form oxide films in trenches, then the process is simple, but the oxide film thickness is not uniform causing void formation
Solution Approach 1:
The patent introduces a nitride film as an intermediary layer between the oxide film and the trench. The nitride film is deposited conformally and then planarized, providing a uniform foundation that enables subsequent oxide film formation with consistent thickness. This intermediary approach maintains ease of manufacture while achieving the manufacturing precision required for uniform oxide film thickness.
4Manufacturing precision
If radical oxidation is used to form gate oxide film uniformly in recess, then the oxide film is uniform, but junction leakage occurs at sidewalls of the recess
Solution Approach 1:
The patent applies a non-uniform gate oxide film thickness profile where the oxide film is thicker at the sidewalls of the recess compared to the center. This local quality variation is achieved through controlled oxidation processes and prevents junction leakage at the sidewalls while maintaining the benefits of radical oxidation for gate oxide film formation.
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 ensures uniform oxide film formation, reduces junction leakage, and improves the refresh time of memory devices by maintaining a lower operating voltage while minimizing the short channel effect.
Implementation Method 1
an oxide film 130 is formed at sidewalls of the trench 120 by a dry oxidation process in the trench 120
Implementation Method 2
a dry oxidation process to form a gate oxide film
Data Source
AI summary
A method for manufacturing a semiconductor device includes forming an oxide film uniformly in a trench in the device isolation by, for example, a radical oxidation process. The method also includes increasing the thickness of the oxide film positioned at recess sidewalls by forming a gate oxide film. Manufacturing the device according to this method will prevent junction leakage and maintain a gate oxidation intensity characteristic that will improve the refresh characteristic of the device.