Capacitance Measurement Transformer Wiring
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Solution Overview
Problem
Current methods for measuring feedback capacitance in semiconductor devices suffer from low accuracy due to wiring inductance and connector contact resistance, especially when longer wiring lengths or higher frequencies are used.
Innovation Solution
A measuring device that includes an LCR meter connected to a semiconductor device via a first transformer and specific wiring configurations, where the wiring is passed through the transformer core only once and wound multiple times around it, to reduce inductive impedance and improve measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the wiring length in the measurement circuit is increased, then the ease of operation and adaptability improve, but the measurement precision deteriorates due to wiring inductance
Solution Approach 1:
A transformer is introduced as an intermediary component between the LCR meter and the semiconductor device under test. The transformer's primary winding connects to the Lc terminal and secondary winding connects to the gate terminal, serving as a mediator that transfers the measurement signal while isolating the measurement circuit from the effects of long wiring inductance. This allows the use of longer wiring for ease of operation without compromising measurement precision.
2Productivity
If the measurement frequency is increased, then the productivity improves, but the measurement precision deteriorates due to increased wiring inductance effects
Solution Approach 1:
The transformer acts as an intermediary that enables high-frequency measurements by isolating the measurement circuit from the semiconductor device. The transformer's magnetic coupling transfers high-frequency signals while blocking the harmful effects of wiring inductance, allowing productivity improvement through higher measurement frequencies without sacrificing precision.
Solution Approach 2:
The electrical connection between the LCR meter and semiconductor device is replaced with a magnetic coupling system through the transformer. This substitution eliminates the direct electrical path that would otherwise be affected by wiring inductance, enabling high-frequency measurements with maintained precision.
3Device complexity
If the two-terminal measurement method is used, then the device complexity is reduced, but the measurement precision deteriorates due to connector contact resistance and wiring inductance
Solution Approach 1:
The transformer is introduced as an intermediary component in the two-terminal measurement setup. By placing the transformer between the Lc terminal and the semiconductor device gate terminal, it mediates the measurement signal transmission while eliminating the adverse effects of connector contact resistance and wiring inductance, thus maintaining measurement precision without increasing 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
The solution significantly improves the measurement accuracy of feedback capacitance by reducing the impact of wiring inductance, allowing for longer wiring lengths and higher measurement frequencies without substantial error.
Implementation Method 1
a first transformer; a first wiring that is passed through a core of the first transformer only once and connected between the gate terminal and the source terminal of the semiconductor device; and a second wiring that is wound N times around the core of the first transformer
Data Source
AI summary
To improve the measurement accuracy of feedback capacitance of a semiconductor device. Between a gate terminal of a semiconductor device subject to measurement and an Lc terminal of an LCR meter, a first wiring that is passed through a core of a transformer once and connected between a gate terminal and a source terminal and a second wiring wound N times around a core of the transformer, and one end is connected to the Lc terminal and the other end is grounded are provided. when ω represents an angular frequency of the AC signal applied to the drain terminal of the semiconductor device, LS_6A represents inductance of the first wiring, LS_6B represents inductance of the second wiring, and CGS represents gate-source parasitic capacitance of the semiconductor device, a relationship of ωLS_6A<1/(ωCGS), and ωLS_6B/N2<1/(ωCGS) are satisfied.