Semiconductor Device Anode Layer Configuration for Voltage Stability
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Solution Overview
Problem
In semiconductor devices with both diode and IGBT regions on the same substrate, the forward voltage in the diode region increases due to reduced positive hole flow from the IGBT region during operation, leading to increased heat loss when gate voltage control is applied.
Innovation Solution
The semiconductor device features first and second anode layers with varying surface areas in proximity to the IGBT region, ensuring increased positive hole injection into the diode drift layer, thereby minimizing the impact of positive holes from the IGBT region and maintaining stable forward voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gate voltage control is applied in the IGBT region during diode operation, then the IGBT region can be controlled, but the forward voltage in the diode region rises and heat loss increases
Solution Approach 1:
The patent applies local quality by creating an n-type channel specifically in the IGBT region while maintaining the diode region's p-type characteristics. The insulated gate structure allows localized channel formation only where needed, preventing the channel from extending into the diode region. This localized approach enables IGBT control functionality without causing the harmful n-type channel formation that would increase forward voltage and heat loss in the diode region.
2Productivity
If the diode region and IGBT region are formed on the same semiconductor substrate, then device integration is achieved, but forward voltage fluctuates due to positive hole flow variations
Solution Approach 1:
The patent segments the semiconductor device into distinct diode region and IGBT region with clear spatial separation. The insulated gate structure acts as a segmentation barrier that prevents the n-type channel formed in the IGBT region from extending into the diode region. This segmentation allows both regions to function independently on the same substrate while maintaining stable forward voltage characteristics in the diode region, as positive hole flow is not disrupted by channel formation.
3Power
If an n-type channel is formed from emitter layer to drift layer in the IGBT region, then IGBT conduction is enabled, but positive holes flowing from IGBT region into diode region are reduced
Solution Approach 1:
The insulated gate structure serves as an intermediary element that mediates between the IGBT region's need for n-type channel conduction and the diode region's need for stable positive hole flow. The gate structure allows the n-type channel to form in the IGBT region for proper IGBT operation while simultaneously acting as a barrier that prevents this channel from extending into the diode region, thereby maintaining the positive hole flow necessary for stable diode forward voltage.
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
This configuration reduces fluctuations in forward voltage and heat loss by enhancing positive hole injection from the anode layers, preventing a rise in diode region voltage.
Implementation Method 1
the amount of positive holes injected from the first anode layer into the diode drift layer increases more than the amount of positive holes injected from the body contact layer into the IGBT drift layer
Implementation Method 2
positive holes flowed from the IGBT region side into the diode region side
Implementation Method 3
an n-type channel is formed from an emitter layer to a drift layer along an insulated gate in the IGBT region
Data Source
AI summary
A semiconductor device in which a diode region and an IGBT region are formed on a same semiconductor substrate is provided. The diode region includes a plurality of first conductivity type anode layers exposed to a surface of the semiconductor substrate and separated from each other. The IGBT region includes a plurality of first conductivity type body contact layers that are exposed to the surface of the semiconductor substrate and separated from each other. The anode layer includes at least one or more of the first anode layers. The first anode layer is formed in a position in the proximity of at least IGBT region, and an area of a plane direction of the semiconductor substrate in each of the first anode layers is larger than the area of a plane direction of the semiconductor substrate in the body contact layer in the closest proximity of the diode region.