Semiconductor Resistor Resistance Compensation Circuit
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Solution Overview
Problem
Integrated circuits with diffused or implanted resistors on semiconductor substrates are sensitive to mechanical stress due to piezoresistivity, leading to variations in electrical parameters and potential functional failure, exacerbated by manufacturing process variability and temperature changes, which makes precise scaling ratios difficult to achieve.
Innovation Solution
An integrated circuit design that includes a semiconductor resistor with a well and L-shaped resistive regions, a tuning element, and a resistance compensation circuit to measure initial resistance and generate voltage for tuning the operating resistance, reducing planar stress sensitivity through precise resistance compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed scaling ratio between P-doped and N-doped resistors is used, then planar stress dependence is theoretically eliminated, but manufacturing process variability causes resistor mismatch and the ratio cannot be precise
Solution Approach 1:
The patent changes the fixed scaling ratio parameter to a dynamically adjustable parameter. By measuring the actual resistance values of P-doped and N-doped resistors and calculating the actual scaling ratio, the system adapts to manufacturing variations. This allows the circuit to compensate for process variability while maintaining planar stress independence.
Solution Approach 2:
The patent implements feedback by measuring the initial resistance values of the resistors and using these measurements to determine the actual scaling ratio. This feedback mechanism allows the system to adjust for manufacturing variations and temperature effects, ensuring accurate current mirroring despite process variability.
2Device complexity
If a fixed scaling ratio is selected, then the circuit design is simple, but temperature variations during IC operation require modification of the ratio
Solution Approach 1:
The patent makes the scaling ratio a temperature-compensated parameter rather than a fixed value. By measuring resistor values at operating temperature and calculating the actual ratio, the system adapts to temperature variations. This maintains current mirroring accuracy across different temperatures without requiring complex temperature compensation circuits.
Solution Approach 2:
The patent performs preliminary measurement of resistor values to determine the actual scaling ratio before the circuit operates. This preliminary action captures the effects of manufacturing variations and temperature, allowing the circuit to be configured with the correct ratio from the start, eliminating the need for continuous adjustment.
3Ease of manufacture
If diffused or implanted resistors are used on semiconductor substrate, then the IC can be manufactured, but the resistors are sensitive to mechanical stress due to piezoresistivity phenomena
Solution Approach 1:
The patent converts the harmful piezoresistive effect into a useful measurement. By measuring the resistance values of P-doped and N-doped resistors, the system detects the effects of mechanical stress and packaging variations. This information is then used to calculate the actual scaling ratio, allowing the circuit to compensate for stress-induced resistance changes and maintain accurate current mirroring.
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 effectively reduces planar stress sensitivity by allowing for real-time adjustment of resistance values, improving the reliability and stability of integrated circuits by compensating for manufacturing and temperature-induced variations.
Implementation Method 1
The resistance compensation circuit may be configured to measure an initial resistance of the first resistive region, and generate a voltage at the tuning element to tune an operating resistance of the first resistive region based upon the measured initial resistance
Implementation Method 2
Diffused or implanted resistors on a semiconductor substrate such as silicon may be sensitive to mechanical stress due to piezoresistivity phenomena
Data Source
AI summary
In one example, a method of compensating resistance in an integrated circuit includes providing a four terminal resistor in a semiconductor substrate. The resistor includes a first resistor and a second resistor coupled in series, a first terminal at a first end of the resistor, a second terminal at a second end of the resistor, a test terminal at a node connecting the first resistor and the second resistor, and a tuning terminal. The first resistor has a first conductivity type and the second resistor has a second conductivity type opposite to the first conductivity type. The first resistor includes a first portion extending along a first direction and a second portion extending along a second direction perpendicular to the first direction. The method further includes computing a voltage to be applied at the tuning terminal to compensate the difference between the resistance of the first and the second resistors.