Semiconductor Device Adjustable Pinch-Off Voltage
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving low and adjustable pinch-off voltage, which is crucial for efficient operation in applications like analog switches and low noise amplifiers, while also requiring cost-effective manufacturing methods.
Innovation Solution
The semiconductor device employs a unique configuration with a substrate, well region, isolation structure, source and drain regions, and a specific doping structure to form an isolated sub-well region without using a mask for the channel, reducing manufacturing costs and allowing for adjustable pinch-off voltage by altering the channel width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional JFET structure is used, then the device can function as an analog switch or amplifier, but the pinch-off voltage cannot be made low and adjustable
Solution Approach 1:
The device divides the well region into multiple doped regions (first doped region surrounding the channel, second doped region underneath the channel) with different conductive types and doping concentrations. This segmentation allows independent control of depletion regions to achieve adjustable pinch-off voltage while maintaining manageable structural complexity
Solution Approach 2:
Different regions of the well are doped with different conductive types and concentrations: the first doped region has one conductive type surrounding the channel, while the second doped region has the opposite conductive type underneath the channel. This local differentiation enables precise control of the depletion region width and pinch-off voltage characteristics
2Manufacturing precision
If mask-based channel formation is used, then the channel width can be precisely defined, but manufacturing costs increase
Solution Approach 1:
The channel width is predetermined by the geometric configuration of the doped regions (first doped region surrounding and second doped region underneath the channel) before any masking steps. This preliminary definition of channel dimensions through doping geometry eliminates the need for additional mask-based channel patterning, reducing manufacturing complexity and cost while maintaining precise channel width control
Solution Approach 2:
The invention extracts and eliminates the mask-based channel formation step from the manufacturing process. Instead, the channel is defined purely by the intersection geometry of the first and second doped regions, removing the need for separate mask alignment and patterning operations for channel definition
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 configuration results in a semiconductor device with a low and adjustable pinch-off voltage, reducing manufacturing costs and enhancing operational efficiency, with the pinch-off voltage achievable as low as −0.2V, suitable for applications such as switching and electrostatic discharge protection.
Implementation Method 1
The channel property and current property of the junction field effect transistor is changed by changing the width of the depletion region in the PN junction between the gate and the source/drain
Implementation Method 2
an electric field near a carrier channel is mostly changed by controlling a signal (or bias of a gate), resulting in the change of the channel property and current property
Implementation Method 3
If the gate voltage is low enough, all the channel is depleted and therefore no current flows from drain to source. The channel which is completely depleted is referred to as being pinched off.
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a substrate; a well region disposed in the substrate; an isolation structure surrounding an active region in the well region; a source region disposed in the well region; a drain region disposed in the well region; a second conductive type first doped region disposed in the well region and disposed along a periphery of the active region; a second conductive type second doped region disposed in the well region and under the source region, the drain region and the second conductive type first doped region, wherein the second conductive type second doped region is in direct contact with the second conductive type first doped region; a source electrode; a drain electrode and a gate electrode. The present disclosure also provides a method for manufacturing the semiconductor device.