Semiconductor Device Trench Gate Field Plate Insulation
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Solution Overview
Problem
Semiconductor devices used in power control face a challenge in achieving a balance between low ON-resistance and high breakdown voltage, as increasing the thickness of the field plate insulating film to enhance breakdown voltage narrows the current path between gate trenches, inhibiting the reduction of ON-resistance.
Innovation Solution
The semiconductor device incorporates a trench gate structure with a field plate electrode and a diode element connected in series, where the diode element has a rectifying property to block leakage current, and the field plate electrode is insulated from the semiconductor part by multiple insulating layers, allowing for a thinner insulating film while maintaining high breakdown voltage, thereby reducing ON-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the field plate insulating film is made thicker to obtain high breakdown voltage, then the breakdown voltage is improved, but the current path between gate trenches becomes narrow which inhibits the reduction of ON-resistance
Solution Approach 1:
The patent introduces a third electrode positioned between the control electrode and the first electrode, creating an additional dimensional layer in the trench structure. This third electrode with its associated insulating films distributes the electrical stress across multiple interfaces, allowing the insulating films to be thinner while maintaining adequate breakdown voltage. The current path is preserved by this layered arrangement, enabling lower ON-resistance without compromising reliability.
Solution Approach 2:
The patent segments the single insulating film structure into multiple insulating films (first insulating film between control electrode and semiconductor part, second insulating film between third electrode and semiconductor part, third insulating film between control electrode and third electrode). This segmentation allows each insulating film to be optimized independently, with thinner individual films that collectively provide the necessary breakdown voltage while preserving current flow paths.
2Reliability
If the field plate insulating film is made thicker to obtain high breakdown voltage, then the breakdown voltage is improved, but the device complexity increases
Solution Approach 1:
The third electrode and its associated insulating films serve multiple functions: they provide additional electrical isolation, distribute voltage stress, maintain current flow paths, and enable thinner individual insulating films. This multi-functionality achieves high breakdown voltage without proportionally increasing device complexity, as the same structural elements serve multiple protective and functional roles.
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 allows for a reduction in ON-resistance by increasing the density of integrated gate trenches while maintaining a high breakdown voltage, ensuring stable voltage across the diode element near its breakdown voltage, thus effectively addressing the balance between ON-resistance and breakdown voltage.
Implementation Method 1
the diode element has a rectifying property to block leakage current
Implementation Method 2
the field plate electrode is insulated from the semiconductor part by multiple insulating layers
Data Source
AI summary
A semiconductor device includes a semiconductor part; first and second electrodes respectively on back and front surfaces of the semiconductor part; a control electrode provided inside a trench of the semiconductor part; a third electrode provided inside the trench; a diode element provided at the front surface of the semiconductor part; a resistance element provided on the front surface of the semiconductor part via an insulating film, the diode element being electrically connected to the second electrode; a first interconnect electrically connecting the diode element and the resistance element, the first interconnect being electrically connected to the third electrode; and a second interconnect electrically connecting the resistance element and the semiconductor part. The resistance element is connected in series to the diode element. The diode element is provided to have a rectifying property reverse to a current direction flowing from the resistance element to the second electrode.