Buried Gate Oxidation Prevention in Semiconductor Devices
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Solution Overview
Problem
Buried gates in semiconductor devices are prone to degradation during thermal processes such as oxidation, which affects the reliability of the devices.
Innovation Solution
A semiconductor device with a buried gate is fabricated using an oxidation prevention barrier and layer to prevent degradation, where the barrier surrounds the region with the buried gate and the layer covers the upper portion, utilizing materials like silicon for the barrier and nitride for the layer to effectively prevent oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a buried gate is formed in a semiconductor device to reduce parasitic capacitance and improve voltage sensing reliability, then the reliability of voltage sensing operation is improved, but the buried gate is prone to degradation during subsequent thermal processes such as oxidation
Solution Approach 1:
An oxidation prevention barrier layer is introduced as an intermediary between the buried gate and the oxidation environment. This barrier layer, formed of materials such as silicon nitride or silicon oxynitride, mediates the interaction by blocking oxygen diffusion to the buried gate during thermal processes, thereby preventing degradation while maintaining the buried gate's original structure and function
Solution Approach 2:
The oxidation prevention barrier creates an inert protective environment around the buried gate by forming a dense, oxygen-impermeable layer. This barrier effectively isolates the buried gate from the oxidizing atmosphere during thermal processes, preventing oxidation and degradation without requiring changes to the buried gate's core structure
2Productivity
If a low-resistance metal layer is used as a gate electrode without forming a polysilicon layer to accommodate small horizontal space, then the integration density is improved, but the buried gate characteristics are degraded during thermal processes
Solution Approach 1:
The oxidation prevention barrier serves as a protective intermediary that shields the low-resistance metal gate electrode from thermal degradation. This barrier layer enables the use of metal gates for high integration density while compensating for the metal's susceptibility to oxidation and degradation during subsequent thermal processes
Solution Approach 2:
The oxidation prevention barrier is formed in advance before subsequent thermal processes occur. This preliminary protective action ensures that when thermal processing is later performed, the buried gate is already protected, allowing the use of low-resistance metal materials without compromising their stability during processing
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
The solution effectively prevents buried gate degradation during thermal processes, ensuring the reliability of the semiconductor device and maintaining the integrity of the gate dielectric layer.
Implementation Method 1
an oxidation prevention barrier surrounding the first region
Implementation Method 2
an oxidation prevention layer covering an upper portion of the first region
Data Source
AI summary
A semiconductor device includes a first region and a second region, a buried gate arranged in the first region, and an oxidation prevention barrier surrounding the first region.