GaN ESD Protection Circuit for Gate Voltage Overshoot

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Solution Overview

Problem

GaN devices are susceptible to damage from electrostatic discharge (ESD) due to their smaller gate-to-source breakdown voltage, which can cause gate voltage overshoot and induce high-intense electric fields and currents, leading to device failure.

Innovation Solution

An ESD protection circuit using GaN-based devices, including resistors, capacitors, and high electron mobility transistors (HEMTs), integrated on a GaN substrate, with a structure that includes power HEMTs and sub-blocks with 2DEG resistors and LV-HEMTs to provide protection against voltage surges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If GaN devices are used for high-power and high-frequency applications, then power consumption is reduced and efficiency is improved, but the devices become susceptible to ESD damage due to smaller gate-to-source breakdown voltage

Engineering Contradiction:

Improvepower consumptionVSAvoidresistance to ESD damage

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces an ESD protection circuit as an intermediary component between the ESD source and the GaN device gate. This circuit includes ESD protection transistors and resistors that act as mediators to detect voltage overshoot conditions and activate protection mechanisms, thereby protecting the GaN device without affecting its normal operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The ESD protection circuit is designed to activate before the ESD damage can occur to the GaN device. The circuit includes early detection mechanisms through voltage dividers and trigger transistors that sense voltage overshoot conditions and preemptively activate protection paths, preventing the harmful ESD current from reaching the vulnerable gate terminal

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If all components in the ESD protection circuit are made using GaN-based devices, then integration is improved and manufacturing is simplified, but the gate-to-source breakdown voltage remains inherently small

Engineering Contradiction:

Improveintegration on GaN substrateVSAvoidgate voltage overshoot susceptibility

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by using different device types with appropriate characteristics in different locations of the protection circuit. Low-voltage HEMTs are used where small breakdown voltage is acceptable or desirable, while other components are optimized for their specific functions. This localized optimization allows the circuit to handle ESD events effectively while maintaining GaN-based integration

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The ESD protection circuit employs a composite structure combining multiple GaN-based device types (HEMTs, resistors, capacitors) with different electrical characteristics. This composite approach allows the circuit to leverage the strengths of each component type while working together to provide comprehensive ESD protection for the overall GaN device system

Inventive Principle:

Principle #40Composite materials

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 circuit effectively protects GaN devices from ESD by establishing controlled conduction paths to dissipate surge currents, reducing the risk of gate damage and enhancing device reliability.

Implementation Method 1

a first 2DEG resistor with one terminal coupled to a first reference voltage, a first trigger with one terminal coupled to another terminal of the first 2DEG resistor and with another terminal coupled to the gate

Methodology Applied

Scientific EffectJoule Heating: Joule Heating

Implementation Method 2

Electrostatic discharge (ESD) is one type of voltage overshoot, resulting from sudden release of electrostatic charges, inducing high intense electric field and current in ICs

Methodology Applied

Scientific EffectElectrostatic Discharge: Electrostatic Discharge

Data Source

PatentUS12609527B2Electrostatic discharge protection circuit using GaN-based devices

Publication Date: 2026.04.21 UNITED MICROELECTRONICS CORP

AI summary

An ESD protection circuit using GaN devices, with a ESD protection block including a first 2DEG resistor with one terminal coupled to a reference voltage, a first trigger with one terminal coupled to the another terminal of the first 2DEG resistor and with another terminal coupled to a gate of a power HEMT, a first LV-HEMT with a first gate coupled to the another terminal of the first 2DEG resistor and a first drain couple to the gate, a second 2DEG resistor with one terminal coupled to the gate, a second trigger with one terminal coupled to another terminal of the second 2DEG resistor and with another terminal coupled to the reference voltage, and a second LV-HEMT with a second gate coupled to the another terminal of the second trigger and a second drain coupled to the first source and a second source coupled to the reference voltage.