Vertical GaN FET on SiC Substrate for High Breakdown Voltage
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Solution Overview
Problem
Current power semiconductor devices face challenges in achieving both high breakdown voltage and high carrier mobility, with silicon carbide devices limited by carrier mobility and nitride semiconductor devices struggling with breakdown voltage.
Innovation Solution
A vertical type GaN-based field effect transistor (FET) is developed, utilizing a GaN-based semiconductor on a silicon carbide substrate with an AlGaN/GaN heterointerface, incorporating a buffer layer to reduce lattice distortion and enhance crystal growth, along with specific electrode and insulating layer configurations to achieve high breakdown voltage and carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a vertical type semiconductor device using silicon carbide is used, then a high breakdown voltage is achieved, but a carrier mobility lower than that of silicon devices results
Solution Approach 1:
The patent employs a composite structure combining silicon carbide substrate with GaN-based semiconductor layers. The silicon carbide provides high breakdown voltage capability while the GaN-based layers contribute high carrier mobility, achieving both requirements simultaneously through material composition rather than single-material limitation
Solution Approach 2:
The invention transitions from conventional lateral type device architecture to vertical type architecture. This dimensional reconfiguration allows the current flow to proceed vertically through the heterostructure layers, enabling the device to exploit the high breakdown voltage of silicon carbide in the vertical direction while maintaining high carrier mobility through the GaN channels
2Reliability
If a lateral type semiconductor device using nitride semiconductor is used, then a high carrier mobility exceeding silicon is achieved, but a high breakdown voltage becomes difficult to obtain
Solution Approach 1:
The patent inverts the conventional lateral type device architecture by adopting vertical type configuration. Instead of having current flow laterally through the nitride semiconductor layers, the vertical architecture directs current flow through the stacked heterostructure, fundamentally changing how the device exploits material properties to simultaneously achieve high carrier mobility and high breakdown voltage
3Reliability
If silicon is used for power semiconductor device, then high carrier mobility is achieved, but breakdown voltage reaches the limit based on physical characteristics of Si
Solution Approach 1:
The patent replaces single-material silicon devices with composite heterostructure devices combining silicon carbide and GaN-based semiconductors. This composite approach allows each material to contribute its superior property: silicon carbide for high breakdown voltage and GaN for high carrier mobility, overcoming the inherent limitations of pure silicon
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 semiconductor device achieves a balance of high breakdown voltage and high carrier mobility, enabling efficient power control in switching and inverter circuits.
Implementation Method 1
incorporating a buffer layer to reduce lattice distortion and enhance crystal growth
Data Source
AI summary
A semiconductor device includes a first semiconductor layer of silicon carbide, a second semiconductor layer of nitride semiconductor, a third semiconductor layer of nitride semiconductor and a drain electrode. The semiconductor device includes a source electrode that has a first projection portion, a conduction electrode that has a second projection portion and a gate electrode. The first semiconductor layer includes a first region, a second region, a third region and a fourth region.