Trench Semiconductor Structure With Guard Region Against Thermal Runaway
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Solution Overview
Problem
Power control semiconductor devices face thermal runaway issues due to overcurrent, leading to increased heat generation and potential element breakdown, as parasitic transistors can be triggered by heat, causing further current and heat increases.
Innovation Solution
Incorporating a guard region with lower thermal conductivity between semiconductor layers to suppress thermal conduction and prevent the parasitic transistor from turning on, thereby preventing thermal runaway and element breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a MOS transistor structure is used to achieve high power control capability, then power control capability is improved, but thermal runaway risk increases due to parasitic transistor activation by heat generation
Solution Approach 1:
The drift region is divided into a first drift region and a second drift region with different doping concentrations. The first drift region has a lower doping concentration than the second drift region, creating distinct thermal zones that segment the heat flow path and prevent uniform temperature rise that would activate the parasitic transistor.
Solution Approach 2:
Different regions of the semiconductor device are given different doping concentrations to create localized thermal properties. The first drift region with lower doping concentration has different thermal characteristics compared to the second drift region, allowing localized heat management that suppresses thermal runaway while maintaining power control capability.
2Power
If high current is allowed to flow to maintain device functionality, then device functionality is maintained, but heat generation increases leading to parasitic transistor activation
Solution Approach 1:
The drift region is segmented into two regions with different doping concentrations, creating distinct thermal zones. This segmentation allows the device to handle high current while distributing heat generation across regions with different thermal properties, preventing localized overheating that would activate the parasitic transistor.
Solution Approach 2:
The doping concentration parameter is changed across different regions of the drift region. The first drift region has a lower doping concentration than the second drift region, which changes the electrical and thermal parameters locally, enabling high current flow while controlling heat generation and temperature distribution.
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 guard region effectively suppresses thermal conduction and prevents temperature increases in the semiconductor device, avoiding thermal runaway and maintaining device stability during overcurrent conditions.
Implementation Method 1
a first region partially provided between the first semiconductor layer and the second semiconductor layer, the first region being provided between the first semiconductor layer and the third semiconductor layer, the first region including a material having a lower thermal conductivity than the first semiconductor layer
Data Source
AI summary
A semiconductor device includes a semiconductor part, a first electrode and control electrodes at the front side of the semiconductor part. The semiconductor part includes first to fourth layers, first and third layers being of a first conductivity type, second and fourth layers being of a second conductivity type. The control electrodes are provided in a plurality of trenches, respectively. The control electrodes include a first control electrode, and a second control electrode next to the first control electrode. The second layer is provided between the first layer and the first electrode. The third and fourth layers are provided between the second layer and the first electrode. The semiconductor part further includes a first region partially provided between the first and second layers. The first region is provided between the first and third layers, the first region including a material having a lower thermal conductivity than the first layer.