Recessed DMOS Electrode Structure for High Breakdown Voltage
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Solution Overview
Problem
Conventional DMOS semiconductor devices face challenges in achieving both high breakdown voltage and low ON-resistance, which are essential for efficient power control.
Innovation Solution
The semiconductor device design includes a recessed structure with an insulating member and a gate insulating film, along with a dual-part electrode configuration, which allows for controlled electric field distribution and reduced ON-resistance, enabling high breakdown voltage and low ON-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional DMOS structure is used, then device simplicity is maintained, but breakdown voltage is limited and ON-resistance cannot be sufficiently reduced
Solution Approach 1:
The electrode is divided into two distinct parts: a first part provided in the recess and a second part provided higher than the insulating member. This segmentation allows independent optimization of each electrode part's function, enabling the first part to control the electric field near the junction while the second part extends the field control to higher regions, thereby achieving higher breakdown voltage without excessive structural complexity
Solution Approach 2:
The electrode structure transitions from a conventional planar configuration to a three-dimensional structure with parts at different vertical levels. The first electrode part is positioned in the recess (lower dimension) while the second part extends above the insulating member (higher dimension), creating a multi-level electrode arrangement that controls the electric field in multiple spatial dimensions, thus improving breakdown voltage
2Reliability
If conventional DMOS structure is used, then manufacturing process is simple, but ON-resistance cannot be sufficiently reduced
Solution Approach 1:
The insulating member is selectively positioned only in a portion of the recess, creating local insulation regions with different properties. This local quality variation allows the electric field to be controlled differently in different areas: concentrated in regions without insulating members for low ON-resistance, and distributed in regions with insulating members for high breakdown voltage, thereby achieving both low ON-resistance and high breakdown voltage
3Productivity
If device size is reduced for high integration density, then integration density improves, but achieving both high breakdown voltage and low ON-resistance becomes more difficult
Solution Approach 1:
The electrode structure utilizes vertical dimensionality with parts at different heights to achieve enhanced breakdown voltage control within a compact lateral footprint. The first electrode part in the recess and the second part above the insulating member create a three-dimensional field control structure that improves performance without proportionally increasing device area, thereby supporting high integration density
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 design achieves increased breakdown voltage and reduced ON-resistance, allowing for efficient power control while enabling device downsizing and high integration density.
Implementation Method 1
The insulating member is provided between the first part and the third layer. The gate insulating film is provided between the semiconductor part and the first part
Implementation Method 2
an insulating member provided in a portion of the recess
Data Source
AI summary
A semiconductor device includes a semiconductor part having a recess formed in an upper surface thereof, an insulating member provided in a portion of the recess, a first electrode, a gate insulating film thinner than the insulating member. The first electrode includes a first part provided in another portion of the recess, and a second part provided higher than the insulating member. The gate insulating film is provided between the semiconductor part and the first part. The semiconductor part includes a first layer of a first conductivity type contacting the gate insulating film, second and third layers of a second conductivity type contacting the first layer and being connected to a source contact and a drain contact. The recess is positioned between the source contact and the drain contact when viewed from above. The insulating member is provided between the first part and the third layer.