SOI S-Contact Resistive Discharge Path for Charge Buildup
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Solution Overview
Problem
Semiconductor devices fabricated on high resistivity substrates face challenges during the manufacturing phase due to trapped charges, which can affect operating characteristics and cause structural damage, particularly in silicon-on-insulator (SOI) devices, where existing discharge paths are complex and require additional components like diodes.
Innovation Solution
A purely resistive discharge path is provided by forming conductive structures that connect drain, source, or gate contacts directly to the high resistivity semiconductor substrate through an insulation layer, eliminating the need for diodes and simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a combination of active diode and junction diode is used to provide a discharge path in SOI devices on low resistivity substrate, then charge discharge functionality is achieved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the diode components from the discharge path structure, replacing them with a simpler conductive structure that directly connects the gate contact to the substrate. This removal of unnecessary components reduces device complexity while maintaining the essential charge discharge functionality through the conductive path formed by the conductive structure.
Solution Approach 2:
The patent changes the electrical parameters of the substrate by using a high resistivity substrate instead of a low resistivity substrate. This parameter change allows the conductive structure to provide both the discharge path functionality and the necessary isolation, eliminating the need for additional diode components and simplifying the overall device structure.
2Reliability
If active layer isolation is used in SOI devices, then device functionality is maintained, but charge discharge path becomes more complex
Solution Approach 1:
The conductive structure serves multiple functions simultaneously: it provides the charge discharge path from the gate contact to the substrate, maintains electrical isolation between the active layer and substrate through the insulation layer, and preserves device functionality. This multi-functionality eliminates the need for separate diode components, simplifying the discharge path structure while maintaining isolation.
3Reliability
If conventional discharge paths with diodes are used, then charge discharge is achieved, but fabrication process complexity increases
Solution Approach 1:
The patent removes the diode fabrication steps from the manufacturing process by replacing diodes with a conductive structure that can be integrated into the existing fabrication flow. This extraction of unnecessary components simplifies the fabrication process while maintaining charge discharge capability through the conductive path.
4Device complexity
If high resistivity substrate is used with simple conductive structure, then device complexity is reduced, but charge discharge effectiveness may be compromised
Solution Approach 1:
The high resistivity substrate parameter enables the conductive structure to provide effective charge discharge by creating appropriate electrical isolation from the substrate while maintaining a clear discharge path. The high resistivity ensures that charges are discharged through the intended conductive path rather than leaking through the substrate, maintaining discharge effectiveness with a simpler structure.
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 solution effectively prevents charge buildup and structural damage during manufacturing, maintaining device functionality while reducing fabrication complexity and ensuring symmetrical charge flow, allowing for negative biasing and improved isolation in SOI devices.
Implementation Method 1
a first conductive structure resistively connecting one of: a) a drain contact or a source contact, and b) a gate contact to the semiconductor substrate
Data Source
AI summary
Systems, methods, and apparatus for an improved protection from charge injection into layers of a device using resistive structures are described. Such resistive structures, named s-contacts, can be made using simpler fabrication methods and less fabrication steps. In a case of metal-oxide-semiconductor (MOS) field effect transistors (FETs), s-contacts can be made with direct connection, or resistive connection, to all regions of the transistors, including the source region, the drain region and the gate.