Semiconductor Device With Floating Trenches For Adjustable Capacitance
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Solution Overview
Problem
Conventional reverse conducting-IGBTs experience increased turn-on power loss due to a tailing voltage shape and high collector-emitter gate capacitance, which is not adjustable, leading to inefficient power conversion in power semiconductor devices.
Innovation Solution
The semiconductor device incorporates gate trench structures with a gate potential electrode and floating trench structures with a floating potential electrode, along with emitter trench structures, on a semiconductor substrate, where the floating trench structures are more numerous in the diode region, allowing for adjustable drain-source capacitance by varying the ratio of emitter and floating trench structures, reducing turn-on power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional RC-IGBT structure with fixed gate trenches is used, then device integration is achieved, but turn-on power loss increases due to uncontrollable gate capacitance
Solution Approach 1:
The gate trench structures are segmented into multiple independent trenches, each with its own electrode. This segmentation allows individual control of capacitance contribution from each trench, enabling adjustable total gate capacitance by selectively connecting or disconnecting specific trench electrodes, thereby reducing turn-on power loss through optimized capacitance control.
Solution Approach 2:
The gate trench structures are designed with dynamic connectivity options, where electrodes in different trenches can be selectively connected to the gate electrode or left floating. This dynamic configuration allows the device to adjust its effective gate capacitance based on operating conditions, optimizing turn-on performance and reducing power loss.
2Adaptability or versatility
If gate trench structures are added to control capacitance, then capacitance adjustability improves, but device structure becomes more complex
Solution Approach 1:
The gate trench structures serve multiple functions: they provide gate control for the IGBT, enable adjustable capacitance through selective electrode connection, and maintain device integration. By making the trench structures multi-functional, the patent achieves capacitance adjustability without proportionally increasing device complexity, as the same structural elements perform multiple roles.
3Loss of energy
If floating trench structures are introduced, then capacitance control improves, but manufacturing process becomes more difficult
Solution Approach 1:
The gate trench structures and floating trench structures are merged into a unified trench system that can be fabricated using the same manufacturing processes. By combining the functionality of gate trenches and floating trenches into a single integrated structure, the patent reduces manufacturing complexity while maintaining the ability to control capacitance and reduce turn-on power loss.
Data Source
AI summary
A semiconductor device including a semiconductor substrate and a plurality of trench structures formed on the semiconductor substrate. The semiconductor substrate includes a first element region for forming an insulated gate bipolar transistor therein, and a second element region for forming a diode therein, the semiconductor substrate constituting a drift layer. The plurality of trench structures includes a plurality of gate trench structures provided on a front surface side of the first element region, each gate trench structure having an electrode provided therein that is based on a gate potential, and a plurality of floating trench structures provided on a front surface side of the second element region, each floating trench structure having an electrode provided therein that has a floating potential.