Voltage-Controlled Resistor Using Dual Doped Wells
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Solution Overview
Problem
Current methods for manufacturing resistors with high resistivities are limited by large sizes and inability to adjust resistivity post-manufacturing, and require additional masks and processes, restricting their application in circuitry.
Innovation Solution
A semiconductor structure comprising a substrate with two doped wells of complementary ions, where the resistivity is controlled by the depth and distance of the wells and varied by differential voltage, allowing for voltage-controlled resistors with high resistivities without additional processes or costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If non-doped polysilicon is used as the resistor, then the size of the resistor is small, but the resistivity is limited to about 1K ohm/sq and additional masks and processes are required
Solution Approach 1:
The invention changes the doping parameters by creating a lightly doped well region with controlled ion concentration, transforming the resistor structure from non-doped polysilicon to a doped semiconductor well, thereby achieving higher resistivity (up to 10K ohm/sq) while maintaining compatibility with standard CMOS manufacturing processes
Solution Approach 2:
The lightly doped well structure serves multiple functions: it acts as the resistor element itself, provides voltage control capability through the well, and can be integrated into standard CMOS工艺流程 without requiring additional mask steps, making the structure universally applicable in mixed-signal circuits
2Manufacturing precision
If a lightly doped well is used to manufacture the resistor, then the resistivity can be controlled by different ion concentrations, but the size of the resistor becomes large
Solution Approach 1:
The invention applies local quality by creating a confined lightly doped well region with specific dimensions and doping concentration only where the resistor is needed, rather than using a large-area structure. The well is formed with controlled depth and lateral dimensions, concentrating the resistive effect in a small localized area while maintaining high resistivity through the light doping
3Ease of manufacture
If conventional resistor structures are used, then the manufacturing process is simple, but the resistors cannot adjust the resistivity once manufactured
Solution Approach 1:
The invention introduces dynamics by making the resistor's effective resistance adjustable through voltage control. The lightly doped well forms a depletion region that can be modulated by applying voltages to the well, dynamically changing the resistive path and enabling post-manufacturing adaptability while maintaining manufacturing simplicity through standard well formation processes
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 enables the creation of small, high-resistivity resistors that can be dynamically controlled by voltage, achieving resistivities greater than 100K ohms with standard manufacturing processes, surpassing conventional resistor capabilities.
Implementation Method 1
A depletion region between the well and the substrate is varied to control resistivity of the semiconductor structure according to a differential voltage applied to the well
Data Source
AI summary
Voltage-controlled semiconductor structures, voltage-controlled resistors, and manufacturing processes are provided. The semiconductor structure comprises a substrate, a first doped well, and a second doped well. The substrate is doped with a first type of ions. The first doped well is with a second type of ions and is formed in the substrate. The second doped well is with the second type of ions and is formed in the substrate. The first type of ions and the second type of ions are complementary. A resistor is formed between the first doped well and the second doped well. A resistivity of the resistor is controlled by a differential voltage. A resistivity of the resistor relates to a first depth of the first doped well, a second depth of the second doped well, and a distance between the first doped well and the second doped well. The resistivity of the resistor is higher than that of a well resistor formed in a single doped well with the second type of ions.