Semiconductor Terminal Capacitance Analysis in ON State
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Solution Overview
Problem
Conventional methods struggle to precisely analyze the terminal capacitance of semiconductor devices, especially when they are in the ON state, due to high current densities making it difficult to measure or calculate the inter-terminal capacitance accurately.
Innovation Solution
An analyzing apparatus that includes a charge amount analyzing unit and a capacitance calculating unit, using a device simulator to analyze the charge amount and calculate terminal capacitance by simulating transient changes and integrating charge density, allowing for precise measurement even in the ON state by applying a displacement voltage smaller than the initial power source voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used to analyze terminal capacitance, then the measurement process is simple, but the measurement precision deteriorates due to large current densities in the ON state
Solution Approach 1:
The patent segments the total current into two distinct components: main current flowing through the semiconductor device and displacement current flowing through the capacitance. By using a simulation circuit with separate branches, the displacement current can be isolated and measured independently from the main current, enabling precise capacitance calculation even in the ON state where large current densities exist.
Solution Approach 2:
The patent introduces a simulation circuit as an intermediary system that replicates the electrical characteristics of the actual semiconductor device. This simulation circuit includes equivalent capacitance elements and current sources that allow the displacement current to be measured indirectly through a controlled environment, avoiding the difficulties of direct measurement in the actual device.
2Measurement precision
If conventional analysis methods are used, then the analysis process is straightforward, but the analysis accuracy deteriorates when the semiconductor device is in the ON state
Solution Approach 1:
The patent performs preliminary analysis of charge amounts in different regions of the semiconductor device before calculating the final capacitance value. The charge amount analyzing unit first determines the charge amounts in the first and second regions separately, then uses these preliminary results to calculate the terminal capacitance, ensuring accurate results even in the ON state.
Solution Approach 2:
The patent employs an iterative analysis process where the charge amount in each region is calculated based on the voltage distribution, and this charge information feeds back into the capacitance calculation. The simulation circuit continuously adjusts the charge distribution based on the applied voltages and boundary conditions, converging to an accurate solution for the terminal capacitance.
Data Source
AI summary
Provided is an analyzing apparatus including a charge amount analyzing unit configured to analyze, by using a device simulator configured to simulate a transient change of a charge in a semiconductor device having a first main terminal and a second main terminal, a change of a charge amount at any one of the terminals when a power source voltage applied between the first main terminal and the second main terminal is changed by a displacement voltage smaller than an initial voltage after a current flowing between the first main terminal and the second main terminal is stabilized with the semiconductor device being set to an ON state and the power source voltage being set to the initial voltage, and a capacitance calculating unit configured to compute a terminal capacitance at any one of the terminals based on the change of the charge amount analyzed by the charge amount analyzing unit.