GaN HEMT Gate Layout With Integrated Schottky Temperature Sensing
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Solution Overview
Problem
Existing temperature measurement methods for power components, particularly GaN-based HEMT transistors, either increase device size or lack accuracy, making it difficult to accurately measure the operating temperature within the transistors.
Innovation Solution
Integrate a Schottky diode within the power microelectronic device by replacing a gate finger with a Schottky contact, forming a temperature sensor that utilizes the Schottky diode to measure the operating temperature, which is integrated within the device and maintains the same breakdown voltage features as the basic transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a metal coil temperature sensor is placed in proximity of the HEMT transistor, then direct temperature measurement is obtained, but the device size increases
Solution Approach 1:
The temperature sensor is merged with the HEMT transistor structure by integrating a Schottky diode formed from the gate finger and drain finger directly within the transistor architecture. This eliminates the need for separate external temperature sensors and reduces overall device size while maintaining measurement capability.
Solution Approach 2:
The gate finger of the HEMT transistor serves dual functions: as a control electrode for the transistor operation and as an electrode for the Schottky diode temperature sensor. This multi-functionality reduces the number of separate components needed and minimizes device area.
2Ease of manufacture
If a conductive bar temperature sensor is placed above the 2DEG circulating in HEMTs, then the sensor is integrated within the HEMT transistor architecture, but the temperature is measured at the side of the transistors rather than accurately within the transistor
Solution Approach 1:
The Schottky diode temperature sensor is positioned locally at the drain finger region where high current density and heating occur, enabling measurement of the actual operating temperature within the transistor rather than at the side. This local positioning ensures accurate temperature measurement at the critical hot spot.
3Measurement precision
If the diode body structure of MOS transistors is used to measure temperature, then temperature can be measured within the transistor, but this method is not applicable to HEMT transistors
Solution Approach 1:
The Schottky diode temperature sensing method is adapted for HEMT transistors by utilizing the gate finger-drain finger structure, which is characteristic of HEMT architecture. This creates a universal solution that works specifically for HEMTs while achieving internal temperature measurement, analogous to the diode body method for MOS transistors.
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 provides accurate temperature measurement close to the actual operating temperature of the transistor, allowing for localized temperature mapping and early detection of hot spots, thereby preventing device failures.
Implementation Method 1
at least one gate finger forms, with the neighbouring drain finger, at least one Schottky-type diode configured to measure an operating temperature within the power microelectronic device
Data Source
AI summary
A power device includes high electron mobility transistors formed on an active layer, each transistor comprising a source finger, a drain finger and a gate finger, a source contact common to the source fingers, a drain contact common to the drain fingers, and a gate contact common to the gate fingers. At least one gate finger is not connected to the gate contact and forms a Schottky contact with the active layer. This gate finger forms, with the neighbouring drain finger, a Schottky diode configured to measure an operating temperature within the power device.