JFET Pinch-Off Voltage Control via Segmented Gate Regions
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Solution Overview
Problem
Existing JFET devices require increased manufacturing costs to achieve lower pinch-off voltage, as current methods involve additional photomasks and processes to adjust doping concentrations in the gate and well regions.
Innovation Solution
The semiconductor device design includes multiple gate regions within the channel region, allowing for adjustment of pinch-off voltage by varying the spacing between these regions, and utilizes existing photomasks for well region formation, thereby avoiding additional manufacturing steps and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If doping concentrations of the gate region and well region are changed to reduce pinch-off voltage, then the pinch-off voltage is reduced, but additional photomasks and processes are required increasing manufacturing cost
Solution Approach 1:
The patent changes the physical configuration parameter of the gate region from a single continuous structure to multiple segmented gate regions. By varying the number of gate regions, their spacing, and dimensions, the pinch-off voltage is controlled without requiring changes to doping concentrations or additional photomasks. This parameter change in geometry rather than material composition resolves the contradiction between achieving precise voltage control and maintaining ease of manufacture.
Solution Approach 2:
The gate region is divided into multiple separate gate regions positioned within the channel region. This segmentation allows the pinch-off voltage to be controlled by the number, spacing, and dimensions of the individual gate regions. The segmented structure achieves the desired electrical characteristics without requiring additional photomasks or process steps, as the multiple gate regions can be formed using the same photomask that defines the well region.
2Manufacturing precision
If additional photomasks and processes are used to adjust doping concentrations, then the pinch-off voltage can be reduced, but the device complexity and manufacturing steps increase
Solution Approach 1:
The photomask used to define the well region is also used to define the multiple gate regions, making this single photomask serve multiple functions. The same photomask pattern simultaneously creates the well region boundaries and the multiple gate region positions. This multi-functionality eliminates the need for additional dedicated photomasks for gate region formation, reducing device complexity while maintaining precise control over the pinch-off voltage through geometric parameters.
3Ease of manufacture
If multiple gate regions are formed with varying spacing, then the pinch-off voltage is reduced without additional photomasks, but the structural complexity of the gate region increases
Solution Approach 1:
The patent transitions from controlling pinch-off voltage through vertical doping concentration gradients to controlling it through horizontal spatial arrangement of multiple gate regions. By utilizing the planar dimension and spacing between multiple gate regions rather than vertical depth variations in doping, the invention achieves voltage control while keeping the fabrication process simple and avoiding additional photomasks.
Data Source
AI summary
A semiconductor device includes a junction field effect transistor (JFET) device. The JFET device includes a substrate, a first well region, a first source region, a first drain region, a first gate region and a second gate region. A channel region is formed between the first source region and the first drain region along a first direction. The first gate region and the second gate region are located within the channel region, the first gate region includes a first surface extending from a top surface to a bottom surface of the first gate region, and the second gate region includes a second surface extending from a top surface to a bottom surface of the second gate region. The first surface is facing a second direction perpendicular to the first direction toward the second surface. A method of manufacturing such semiconductor device is also provided.