Buried Doped Isolation Region with Varying Concentration

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Solution Overview

Problem

Semiconductor devices with buried doped isolation regions face reduced breakdown voltage due to high electric fields at corner areas, which are not effectively addressed by existing technologies.

Innovation Solution

A continuous buried doped isolation region with a net first conductivity type doping concentration of varying levels, where the interior area has a higher doping concentration and the corner areas have a lower doping concentration, reducing peak electric fields and enhancing breakdown voltage characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a continuous buried doped isolation region with uniform high doping concentration is used, then isolation effectiveness is improved, but breakdown voltage in corner areas deteriorates due to high peak electric fields

Engineering Contradiction:

Improveisolation effectivenessVSAvoidbreakdown voltage

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a non-uniform doping concentration distribution within the buried isolation region. Specifically, the doping concentration is reduced in corner areas compared to the interior regions, allowing each area to have optimized electrical characteristics. This local differentiation resolves the contradiction by maintaining high isolation effectiveness in interior areas while reducing peak electric fields and improving breakdown voltage in corner areas.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the doping concentration parameter spatially within the buried isolation region. By varying the doping concentration from high in interior areas to lower in corner areas, the patent optimizes both isolation effectiveness and breakdown voltage characteristics. This parameter variation allows the system to achieve both contradictory goals simultaneously through controlled modification of the electrical properties in different spatial locations.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If doping concentration is increased to improve isolation, then isolation effectiveness is improved, but peak electric fields in corner areas increase reducing breakdown voltage

Engineering Contradiction:

Improveisolation effectivenessVSAvoidpeak electric fields

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent converts the harmful effect of high peak electric fields in corner areas by intentionally reducing the doping concentration in those specific locations. This strategic reduction transforms the corner areas from high-risk regions with high electric fields to regions with optimized field distribution, thereby improving overall device reliability while maintaining isolation effectiveness in other areas.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 approach effectively increases breakdown voltage in corner areas by up to 50% by reducing peak electric fields, improving the isolation and operational efficiency of semiconductor devices.

Implementation Method 1

reducing peak electric fields and enhancing breakdown voltage characteristics

Methodology Applied

Scientific EffectElectric Field: Electric Field

Implementation Method 2

continuous buried doped isolation region with a net first conductivity type doping concentration of varying levels

Methodology Applied

Scientific EffectDoping: Dopants

Data Source

PatentUS10607880B2Die with buried doped isolation region

Publication Date: 2020.03.31 NXP USA INC

AI summary

A continuous buried doped isolation region in a substrate of a die. The substrate includes an isolation ring structure surrounding a first area of the die. The continuous buried doped isolation region is of a net first conductivity type and is located in the first area. The continuous buried doped isolation region including a first portion having a net first conductivity type dopant concentration of at least a first level located in an interior region of the first area and extending to a sidewall of the isolation ring structure. The first portion does not extend to the sidewall of the isolation ring structure in a location of a corner area of the first area. The corner area is defined by the isolation ring structure. A second portion of the continuous buried doped isolation region in the corner area has a net first conductivity type dopant concentration of a second level that is lower than the first level. The die comprises a semiconductor device located in the first area and including components located in the substrate in the first area above the continuous buried doped isolation region.