Semiconductor Device Porous Oxide Field Reduction
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Solution Overview
Problem
Conventional semiconductor devices face challenges in maintaining breakdown voltage characteristics due to non-uniform field distribution caused by external charges, which leads to an expansion of the termination structure portion.
Innovation Solution
The semiconductor device incorporates a semiconductor substrate with an electric-field reduction region, including a porous-oxide-film region and floating electrodes, which reduces the dielectric constant and extends deeper than the trench, coupled with a channel stopper region to maintain breakdown voltage without expanding the termination structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulator region is formed between guard ring region and channel stopper region to reduce charge influence, then breakdown voltage characteristic is improved, but termination structure portion area is expanded
Solution Approach 1:
The patent employs a porous oxide film region with lower dielectric constant than conventional insulator regions. This porous structure reduces the dielectric constant in the termination structure portion, which helps distribute electric field more uniformly and reduces charge accumulation effects without requiring expansion of the termination structure area. The porous oxide film achieves the same charge mitigation function in a more compact space.
Solution Approach 2:
The patent changes the dielectric constant parameter by introducing a porous oxide film region with lower dielectric constant compared to conventional insulator regions. This parameter change allows the termination structure to maintain breakdown voltage characteristics while occupying less area, as the lower dielectric constant material inherently provides better charge dissipation and field distribution.
2Reliability
If termination structure portion is expanded to ensure breakdown voltage, then breakdown voltage characteristic is improved, but device area is increased
Solution Approach 1:
The porous oxide film region with lower dielectric constant enables the termination structure to maintain adequate breakdown voltage characteristics without requiring large area expansion. The reduced dielectric constant material provides better electric field distribution and charge management within a compact footprint.
Solution Approach 2:
The patent uses a composite structure combining porous oxide film region with conventional insulator regions and doped regions. This composite approach allows optimization of electrical characteristics within a compact area, achieving breakdown voltage assurance without excessive device area expansion.
3Ease of manufacture
If conventional insulator region is used in termination structure, then manufacturing is simplified, but charge accumulation causes non-uniform field distribution
Solution Approach 1:
The porous oxide film region provides a material solution that addresses field distribution uniformity while maintaining manufacturing feasibility. The porous structure inherently offers lower dielectric constant and better charge dissipation properties, reducing field non-uniformity caused by charge accumulation during packaging processes.
Solution Approach 2:
By changing the dielectric constant parameter through porous oxide film formation, the patent achieves more uniform field distribution that is less sensitive to charge accumulation. This parameter change makes the field distribution more stable under varying manufacturing conditions.
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 effectively maintains breakdown voltage characteristics by dividing the electric potential and spacing electric potential contours, preventing distortion and ensuring stable breakdown voltage without expanding the termination structure portion.
Implementation Method 1
The insulating region is formed from the first main surface to a predetermined depth and has a lower dielectric constant than a predetermined dielectric constant
Implementation Method 2
The plurality of floating electrodes are arranged so that the electrodes have coupling capacitor components along a direction connecting the element-formed region and the channel stopper region
Implementation Method 3
The channel stopper region of the first conductivity type is formed opposite to the element-formed region with respect to the insulating region and spaced from the insulating region
Data Source
AI summary
In one surface of a semiconductor substrate, an active region in which main current flows and an IGBT is disposed is formed. A termination structure portion serving as an electric-field reduction region is formed laterally with respect to the active region. In the termination structure portion, a porous-oxide-film region, a p-type guard ring region, and an n+-type channel stopper region are formed. A plurality of floating electrodes are formed to contact the surface of the porous-oxide-film region. Another plurality of floating electrodes are formed to contact a first insulating film.