GaN Diode Between Gate and Source for Breakdown Protection
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Solution Overview
Problem
GaN-based semiconductor devices with AlGaN/GaN heterojunction channels are normally on type and prone to gate electrode breakdown under excessive positive voltage, requiring additional diodes to protect the gate, which increases circuit complexity and part count.
Innovation Solution
A semiconductor device with a diode formed between the gate and source electrodes on the same chip, using a Schottky barrier junction or ohmic contact with the substrate, providing electrical insulation and reducing interconnection length to protect the gate electrode without increasing chip area or manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diode is provided between gate and source outside a chip to protect the gate electrode, then the gate electrode is protected from breakdown, but the number of parts increases and interconnections on circuit substrate become complicated
Solution Approach 1:
The patent merges the protective diode function with the existing transistor structure by forming the diode within the same chip using the same gate electrode, source electrode, and semiconductor substrate. This integration eliminates the need for separate external diode components and their associated interconnections, thereby reducing circuit complexity while maintaining gate electrode protection functionality.
2Reliability
If a diode is provided between gate and source outside a chip to protect the gate electrode, then the gate electrode is protected from breakdown, but the number of parts of circuit increases
Solution Approach 1:
The protective diode is merged with the transistor structure by utilizing the gate electrode as one terminal of the diode and forming the diode's semiconductor region within the same chip. This integration reduces the total number of discrete parts by eliminating the need for separate external diode components while maintaining the protective function.
3Reliability
If the diode forming area is insulated from the transistor forming area, then electrical insulation is achieved, but the chip area increases
Solution Approach 1:
The patent implements electrical insulation between the diode forming area and transistor forming area through vertical layering of insulating films rather than horizontal separation. Multiple insulating films are stacked in the vertical dimension to provide adequate electrical isolation, allowing the diode and transistor to be positioned closer together horizontally and reducing the overall chip area.
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 protects the gate electrode from breakdown while maintaining high-frequency characteristics and low on-state resistance, reducing parasite components and manufacturing costs by integrating the diode within the existing process without adding new steps.
Implementation Method 1
a first diode electrode in which a gate electrode of the field-effect transistor is placed in Schottky barrier junction and/or ohmic contact with the semiconductor substrate
Data Source
AI summary
A semiconductor device of an embodiment includes: a semiconductor substrate; a field-effect transistor formed on the semiconductor substrate; and a diode forming area which is adjacent to a forming area of the field-effect transistor, wherein the diode forming area is insulated from the forming area of the transistor on the semiconductor substrate, and includes a first diode electrode in which a gate electrode of the field-effect transistor is placed in Schottky barrier junction and/or ohmic contact with the semiconductor substrate through a bus wiring or a pad; and a second diode electrode in which a source electrode of the field-effect transistor is placed in ohmic contact and/or Schottky barrier junction with the semiconductor substrate through a bus interconnection or a pad to form a diode between the gate electrode and the source electrode.