Level Shifter Gate Resistance Layout for ESD Protection
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Solution Overview
Problem
Semiconductor devices in level shifters with thin gate insulating layers are vulnerable to electrostatic discharge (ESD) stress due to limited driving current, which can lead to destruction of the gate insulating layer, necessitating effective ESD protection to prevent damage and noise interference.
Innovation Solution
Incorporating a resistor on the gate of the semiconductor device and interconnecting a back-to-back diode to the ground line to increase gate resistance and facilitate efficient discharge of ESD stress, thereby protecting the thin gate insulating layer and core devices from ESD and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a thin gate insulating layer is used in a semiconductor device in a level shifter, then driving current capability is improved, but vulnerability to ESD stress increases
Solution Approach 1:
A resistor is introduced as an intermediary element connected to the gate of the semiconductor device. This resistor increases the gate resistance, which limits the ESD current flowing into the thin gate insulating layer while allowing normal operating signals to pass through. The resistor acts as a mediator that protects the vulnerable gate oxide from ESD damage without affecting the driving current capability during normal operation.
2Reliability
If gate resistance is increased to reduce ESD stress, then protection against ESD is improved, but driving current capability deteriorates
Solution Approach 1:
The resistor is applied locally only to the gate terminal of the semiconductor device, not to the entire circuit. This localized application increases gate resistance specifically for ESD protection purposes while maintaining low resistance in the main current path. The local modification allows the gate to have high resistance for protection during ESD events, while the source-drain path maintains low resistance for high driving current capability during normal operation.
3Reliability
If a back-to-back diode is added to discharge ESD stress, then ESD protection is improved, but device complexity increases
Solution Approach 1:
Back-to-back diodes are added to provide a dedicated ESD discharge path. During normal operation, these diodes remain non-conductive and do not affect circuit functionality. When ESD stress occurs, the diodes become conductive and provide a low-impedance path to discharge the ESD current away from the vulnerable semiconductor device. This converts the potentially harmful ESD energy into a controlled discharge process, protecting the device without significantly increasing 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 effectively prevents damage to the thin gate insulating layer and enhances the semiconductor device's resistance to ESD stress and noise, ensuring reliable operation by providing a robust ESD protection mechanism.
Implementation Method 1
adds a resistor on a gate used in a semiconductor device in a level shifter, thereby relieve an ESD or EOS stress
Implementation Method 2
interconnecting a back-to-back diode to a ground line to increase gate resistance and facilitate efficient discharge of ESD stress
Data Source
AI summary
The present disclosure relates to a semiconductor chip having a level shifter with electro-static discharge (ESD) protection circuit and device applied to multiple power supply lines with high and low power input to protect the level shifter from the static ESD stress. More particularly, the present disclosure relates to a feature to protect a semiconductor device in a level shifter from the ESD stress by using ESD stress blocking region adjacent to a gate electrode of the semiconductor device. The ESD stress blocking region increases a gate resistance of the semiconductor device, which results in reducing the ESD stress applied to the semiconductor device.