Semiconductor Sense Resistor Segmentation for Thermal Stability
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Solution Overview
Problem
Existing sense resistors in electronic devices, such as class-D amplifiers, face measurement inaccuracies due to temperature fluctuations, particularly when located close to power stages, as they are influenced by materials with high temperature coefficients, leading to erroneous current value determinations.
Innovation Solution
The design incorporates a sense resistor with a resistive body and sense terminals constructed using materials with different temperature coefficients, where the sense terminals are decoupled from the resistive head and body, utilizing silicide blocking to reduce the impact of temperature variations and metal interconnect effects, thereby facilitating more accurate voltage and current sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If sense resistors are located close to power stages for compact design, then device integration is improved, but measurement precision deteriorates due to temperature fluctuations and high temperature coefficients of materials
Solution Approach 1:
The sense resistor structure is segmented into distinct functional regions: a resistive body region for current sensing and sense terminal regions for voltage measurement. This segmentation allows the resistive body to be positioned close to power stages while the sense terminals are located in temperature-stable regions, separating the functions to resolve the contradiction between compact integration and measurement precision.
Solution Approach 2:
Different regions of the sense resistor are assigned different material properties: the resistive body uses materials optimized for low temperature coefficients, while sense terminals use materials with appropriate contact properties. This local differentiation of material quality allows the structure to simultaneously achieve compact integration and temperature-stable measurements by optimizing each region for its specific function.
2Device complexity
If traditional sense resistor structures with coupled terminals are used, then device complexity is reduced, but measurement precision deteriorates due to temperature-induced errors and metal interconnect effects
Solution Approach 1:
The sense resistor is divided into a resistive body portion and separate sense terminal portions that are decoupled from each other. The sense terminals are further segmented into first and second sections, with the second section having an end portion that couples to the resistive body. This segmentation enables independent optimization of each region and eliminates the measurement errors caused by temperature-induced expansion and metal interconnect effects that plague traditional coupled structures.
Solution Approach 2:
The second section of the sense terminal acts as an intermediary element between the first section and the resistive body. This intermediary structure, with its specific material composition and geometric configuration, provides a controlled transition zone that reduces the impact of temperature variations and metal interconnect effects on the voltage measurement, thereby improving measurement precision without significantly increasing overall device complexity.
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 significantly reduces measurement errors caused by temperature fluctuations, achieving a three-times reduction in error spread and a five-times reduction in mean error across temperature variations, ensuring accurate current measurements and improved device performance.
Implementation Method 1
The resistor body is coupled to the resistor head and is constructed using a second material having a higher resistivity than the first material
Data Source
AI summary
A semiconductor device includes a resistor head, a resistor body, and a sense terminal. The resistor head is constructed using a first material. The resistor body is coupled to the resistor head and is constructed using a second material having a higher resistivity than the first material. The sense terminal has a first section and a second section and is decoupled from the resistor head, in which the second section of the sense terminal is coupled between the first section of the sense terminal and the resistor body, with an end portion of the second section of the sense terminal coupled to the resistor body.