GaN Power Structure With Variable Field Plates for Breakdown Control
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Solution Overview
Problem
The efficiency of silicon-based power devices is limited, and there is a need for improved power conversion systems that can effectively control current flow through on/off switching, which existing technologies have not adequately addressed.
Innovation Solution
A power device design incorporating a channel layer, source, drain, gate, passivation layer, and field plates with varying thicknesses and widths, along with a depletion forming layer to create a two-dimensional electron gas, enhancing electron mobility and allowing for a normally-off state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If silicon-based power devices are used, then manufacturing process is well-established, but efficiency improvement is limited due to material constraints
Solution Approach 1:
The patent changes the fundamental material parameter from silicon to GaN (gallium nitride), which has superior electron mobility and breakdown voltage characteristics. This material substitution enables higher efficiency power conversion while overcoming the inherent limitations of silicon-based devices
Solution Approach 2:
The device employs a heterojunction structure combining GaN channel layer with AlGaN barrier layer, creating a composite semiconductor structure that leverages the complementary properties of different III-V compound semiconductors to achieve enhanced performance
2Reliability
If field plates with varying thicknesses are implemented, then breakdown voltage increases and capacitance reduces, but manufacturing process complexity increases
Solution Approach 1:
The patent applies local quality by varying the thickness of field plates at different locations along the drain region. The field plates have different thicknesses (first thickness near gate, second thickness farther from gate), creating localized electric field control that optimizes breakdown voltage and reduces capacitance in specific regions
Solution Approach 2:
The invention introduces thickness variation as an additional dimensional parameter for field plate design. Instead of uniform planar field plates, the structure extends in the vertical dimension with graduated thickness levels, enabling sophisticated electric field management without proportionally increasing planar footprint
3Speed
If depletion forming layer is added to create 2DEG, then high electron mobility is achieved, but device structure becomes more complex
Solution Approach 1:
The patent replaces conventional doping-based carrier generation with a quantum mechanical effect (2DEG formation at heterojunction interface). The AlGaN/GaN heterostructure naturally forms a two-dimensional electron gas with high mobility through polarization-induced charge accumulation, eliminating the need for complex doping processes
Solution Approach 2:
The invention changes the fundamental mechanism of carrier generation from thermal/doping-based to quantum confinement-based 2DEG formation. By adjusting the Al composition ratio in AlGaN barrier layer and controlling layer thicknesses, the patent optimizes 2DEG density and mobility parameters
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 design increases breakdown voltage, reduces capacitance, and improves high power and high frequency performance by effectively controlling the electric field and shielding effects, thereby overcoming the limitations of silicon-based devices.
Implementation Method 1
The barrier layer may be configured to form a two dimensional electron gas (2DEG) in the channel layer
Implementation Method 2
The depletion forming layer may be configured to form a depletion region in the 2DEG
Implementation Method 3
a plurality of field plates in the passivation layer. The plurality of field plates may have different thicknesses
Data Source
AI summary
Provided are a power device and a method of manufacturing the same. The power device may include a channel layer; a source and a drain at respective sides of the channel layer; a gate on the channel layer between the source and the drain; a passivation layer covering the source, the drain, and the gate; and a plurality of field plates in the passivation layer. The plurality of field plates may have different thicknesses. The plurality of field plates may have different widths, different pattern shapes, or both different widths and different pattern shapes.