III-N Heterostructure Schottky Diodes with 2DEG
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Solution Overview
Problem
Existing semiconductor diodes face a trade-off between high blocking voltages and low on-resistance, with Schottky diodes exhibiting large reverse leakage currents and PIN diodes having high conduction and switching losses, making them unsuitable for high voltage applications.
Innovation Solution
The development of semiconductor Schottky diodes with a two-dimensional electron gas (2DEG) to reduce on-resistance and conduction losses, incorporating features like field plates to increase breakdown voltage and a Schottky barrier that is not lowered during reverse bias operation, integrated with III-N material layers and transistors on a common substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If Schottky diodes are used for high voltage switching, then switching speed and on-state performance are improved, but reverse leakage current increases
Solution Approach 1:
The patent changes the material parameters by transitioning from silicon to III-N heterostructure materials, which fundamentally alters the electrical characteristics to achieve both high switching speed and low reverse leakage current through the formation of 2DEG and high breakdown electric field
Solution Approach 2:
The patent employs composite material structure with III-N heterojunction forming a two-dimensional electron gas channel, combining the advantages of different materials to achieve high electron mobility for fast switching and high breakdown field for low leakage current
2Object-generated harmful factors
If high voltage Si PIN diodes are used to support large reverse bias voltages, then reverse leakage is reduced, but conduction losses and switching losses increase
Solution Approach 1:
The patent changes the conduction mechanism by utilizing the high-mobility 2DEG channel in III-N heterostructure, which reduces on-resistance and conduction losses while maintaining high breakdown voltage capability through the material's intrinsic properties
Solution Approach 2:
The patent creates a localized high-mobility 2DEG channel region within the III-N heterostructure that provides low-resistance conduction path during forward bias, while the bulk material maintains high breakdown field strength for low leakage during reverse bias
3Strength
If reverse bias voltage is increased to support high voltage applications, then blocking capability is improved, but Schottky barrier lowering occurs resulting in increased reverse bias currents
Solution Approach 1:
The patent changes the barrier characteristics by utilizing the polarization-induced 2DEG and high breakdown field of III-N materials, which prevents Schottky barrier lowering at high reverse biases through the material's high critical electric field strength
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 achieves low on-resistance, high breakdown voltage, and low reverse leakage currents, enabling efficient high voltage switching while maintaining low switching losses and facilitating integration with other circuit components for cost reduction.
Implementation Method 1
a 2DEG channel is in the first III-N material layer because of a compositional difference between the first III-N material layer and the second III-N material layer
Implementation Method 2
Metal layer 7 forms a Schottky anode contact to layer 4
Data Source
AI summary
Planar Schottky diodes for which the semiconductor material includes a heterojunction which induces a 2DEG in at least one of the semiconductor layers. A metal anode contact is on top of the upper semiconductor layer and forms a Schottky contact with that layer. A metal cathode contact is connected to the 2DEG, forming an ohmic contact with the layer containing the 2DEG.