MOS Back-Gate ESD Circuit for Stable Dual-Polarity Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The semiconductor device described in Japanese Unexamined Patent Application Publication No. JP2011254100A faces an issue where the discharge path for electrostatic protection varies with polarity, leading to an increased circuit area for the electrostatic destruction protection circuit.
Innovation Solution
A semiconductor device is designed with a MOS transistor coupled between two terminals and a diode between the back gate of the MOS transistor and one terminal, with a polarity reverse to the parasitic diode formed between the back gate and source, to effectively discharge static electricity and reduce the circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate discharge paths are provided for positive and negative static electricity, then protection reliability is improved, but circuit area increases
Solution Approach 1:
The MOS transistor serves multiple functions: it acts as a discharge path for both positive and negative static electricity, functions as a protection element for the parasitic diode, and can be controlled via the back gate. This multi-functionality eliminates the need for separate discharge paths for different polarities, reducing circuit area while maintaining protection reliability.
Solution Approach 2:
The back gate serves as an intermediary control element that regulates the discharge path. By applying appropriate voltages to the back gate, the MOS transistor can be selectively activated to handle different static electricity polarities, enabling a single circuit element to perform what would traditionally require multiple dedicated paths.
2Adaptability or versatility
If the discharge path varies with static electricity polarity, then protection adaptability is improved, but device complexity increases
Solution Approach 1:
The discharge path is made dynamic through voltage-controlled activation of the MOS transistor. The back gate voltage dynamically adjusts the transistor's conductivity state, enabling the circuit to adapt to different static electricity polarities without requiring separate static discharge paths. This dynamic control simplifies the overall circuit structure compared to multiple fixed discharge paths.
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 reduces the circuit area required for the electrostatic destruction protection circuit by stabilizing the discharge path for both positive and negative electrostatic surges, allowing for a more compact design and increased arraying of input/output interface circuits.
Implementation Method 1
a diode which is coupled between a back gate of the MOS transistor and one of the terminals and has a polarity which is reverse to the polarity of a parasitic diode which is formed between the back gate and a source of the MOS transistor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A semiconductor device includes a MOS transistor which is coupled between two terminals and discharges current which flows caused by generation of static electricity and a diode which is coupled between a back gate of the MOS transistor and one of the terminal and has a polarity which is reversed to the polarity of a parasitic diode which is formed between the back gate and a source of the MOS transistor.