GaN Field Plate Structure for Breakdown and Capacitance Control
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Solution Overview
Problem
The efficiency of silicon-based power devices is limited, and existing power conversion systems face challenges in improving conversion efficiency due to silicon properties and manufacturing processes, necessitating the development of alternative materials and structures like group III-V compound semiconductors for enhanced performance.
Innovation Solution
A power device design incorporating a channel layer with a GaN-based material, a barrier layer to form a two-dimensional electron gas, and a depletion forming layer, along with a passivation layer containing field plates of varying thicknesses and widths, which are formed using a method involving photoresist layers, etching patterns, and microloading effects to optimize electrical properties and breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If silicon-based materials are used in power devices, then manufacturing processes are well-established, but conversion efficiency cannot be improved further due to material limitations
Solution Approach 1:
The patent changes the fundamental material parameter from silicon to GaN-based compound semiconductors, enabling higher breakdown voltages and improved conversion efficiency that cannot be achieved with silicon-based materials
Solution Approach 2:
The patent employs a heterojunction structure combining different GaN-based materials with varying bandgaps and material properties to create a composite semiconductor structure that optimizes both efficiency and electrical performance
2Reliability
If field plates with uniform thickness are used, then manufacturing is simpler, but electric field control and breakdown voltage are insufficient
Solution Approach 1:
The patent applies local quality by varying the thickness of field plates at different locations, with thicker field plates positioned where higher electric field control is needed and thinner field plates where less control is required
Solution Approach 2:
The field plate structure is segmented into multiple regions with different thicknesses, allowing independent optimization of electric field control in each region to enhance overall breakdown voltage
3Reliability
If larger field plates are used, then electric field control is improved, but capacitance between gate and drain increases
Solution Approach 1:
The patent uses local quality by implementing field plates with spatially varying thicknesses, providing strong electric field control only in regions where it is most needed while minimizing capacitance in other areas
Solution Approach 2:
The patent transitions from uniform two-dimensional field plates to three-dimensional structures with varying thickness, enabling improved electric field control without proportionally increasing gate-drain capacitance
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 achieves a normally-off state with improved breakdown voltage and high-frequency, high-power performance by controlling the electric field and reducing capacitance between the gate and drain, enhancing the overall efficiency of the power device.
Implementation Method 1
The barrier layer may be configured to form a two dimensional electron gas (2 DEG) in the channel layer
Implementation Method 2
The depletion forming layer may be configured to form a depletion region in the 2 DEG
Implementation Method 3
a plurality of field plates in the passivation layer... distances between the channel layer and the plurality of field plates may increase along a direction from the gate toward the drain
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.