Porous Metallic Gate Electrode via PEALD for Gas Sensors
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Solution Overview
Problem
Existing gas sensor devices with porous catalytic metal gate electrodes face challenges in controlling the thickness and porosity of nanoparticle compound pastes, leading to variations and discontinuities during the drying/sintering process, affecting sensitivity and reliability.
Innovation Solution
The method involves using plasma enhanced atomic layer deposition (PEALD) to form a porous metallic gate electrode on a substrate, allowing for precise control of thickness, nanoparticle size, and porosity, enabling the formation of a uniform and sensitive gas-sensitive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If nanoparticle compound paste is used to form porous catalytic metal gate electrode, then surface area and sensitivity are improved, but manufacturing precision and uniformity deteriorate due to difficulty in controlling thickness and porosity
Solution Approach 1:
The patent changes the deposition parameters by using atomic layer deposition (ALD) instead of conventional paste application methods. ALD allows precise control of film thickness through controlled number of deposition cycles, each adding a known thickness, thereby achieving uniform and controllable gate electrode thickness while maintaining the desired porous structure for high sensitivity
Solution Approach 2:
The patent replaces the mechanical paste application and drying/sintering process with a vapor-phase deposition process (ALD). This substitution eliminates the mechanical handling issues of paste application, preventing cracking and discontinuity while enabling precise thickness control through vapor deposition layers
2Measurement precision
If nanoparticle compound paste is used to form porous catalytic metal gate electrode, then surface area is improved, but reliability deteriorates due to cracking and discontinuity during drying/sintering
Solution Approach 1:
The patent replaces the mechanical paste application and thermal processing with vapor-phase atomic layer deposition. This eliminates the drying and sintering steps that cause cracking and discontinuity, producing a continuous and reliable porous metal layer through controlled vapor deposition
Solution Approach 2:
The patent creates a porous metal structure through controlled ALD deposition conditions, where the porous nature is achieved through the deposition process itself rather than through paste formulation and thermal processing. This maintains the high surface area needed for sensitivity while ensuring structural continuity and reliability
3Quantity of substance
If nanoparticle compound paste is applied, then catalytic material coverage is achieved, but device complexity increases due to difficult process control
Solution Approach 1:
The patent replaces complex paste formulation and application processes with the simpler and more controllable vapor-phase ALD process. The automated sequential deposition of precursors in ALD reduces manual intervention and process variability, simplifying manufacturing while ensuring complete and uniform catalytic material coverage
Solution Approach 2:
The ALD process incorporates self-limiting surface reactions that provide inherent feedback control. Each deposition cycle completes only when the surface is saturated, automatically preventing over-deposition and ensuring uniform coverage without requiring complex process monitoring and adjustment
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 results in a highly sensitive and reliable gas sensor device with improved control over the gate electrode's properties, enhancing detection capabilities for target gases without the issues of cracking or discontinuity.
Implementation Method 1
forming a porous metallic gate region above the insulator layer using plasma enhanced atomic layer deposition (PEALD)
Implementation Method 2
forming a porous metallic gate region above the insulator layer using plasma enhanced atomic layer deposition (PEALD)
Data Source
AI summary
A method of fabricating a semiconductor sensor device includes providing a substrate, supporting a source region and a drain region with the substrate, forming an insulator layer above the source region and the drain region, and forming a porous metallic gate region above the insulator layer using plasma enhanced atomic layer deposition (PEALD).