Transistor Drift Region Doping for Breakdown and On-Resistance

Solution Overview

Problem

The semiconductor industry faces challenges in producing high voltage transistors with both high breakdown voltage and low on-resistance, often requiring a large number of processing steps that increase costs.

Innovation Solution

A semiconductor device with a drift region formed into multiple carrier charge zones and carrier adjustment regions, using fewer processing steps to achieve a uniform electric field and reduced on-resistance, including a method of forming these zones with varying doping concentrations and counter-doping techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If various doped regions are formed to achieve high breakdown voltage and low on-resistance, then the transistor performance is improved, but the number of processing steps increases

Engineering Contradiction:

Improvebreakdown voltage and on-resistanceVSAvoidnumber of processing steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The drift region is segmented into multiple zones (first zone, second zone, third zone) with different doping concentrations, allowing each zone to contribute differently to breakdown voltage and on-resistance. This segmentation enables achieving both high breakdown voltage and low on-resistance within a single integrated structure rather than requiring separate doped regions formed through multiple processing steps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different zones within the drift region have different doping concentrations tailored to their specific functions: the first zone has a first doping concentration, the second zone has a second doping concentration, and the third zone has a third doping concentration. This local quality variation allows optimization of both breakdown voltage and on-resistance properties in different spatial regions without requiring additional processing steps.

Inventive Principle:

Principle #3Local quality

2Reliability

If various doped regions are formed to achieve high breakdown voltage and low on-resistance, then the transistor performance is improved, but the manufacturing cost increases

Engineering Contradiction:

Improvebreakdown voltage and on-resistanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The drift region is segmented into multiple zones (first zone, second zone, third zone) with different doping concentrations, allowing each zone to contribute differently to breakdown voltage and on-resistance. This segmentation enables achieving both high breakdown voltage and low on-resistance within a single integrated structure rather than requiring separate doped regions formed through multiple processing steps.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different zones within the drift region have different doping concentrations tailored to their specific functions: the first zone has a first doping concentration, the second zone has a second doping concentration, and the third zone has a third doping concentration. This local quality variation allows optimization of both breakdown voltage and on-resistance properties in different spatial regions without requiring additional processing steps.

Inventive Principle:

Principle #3Local quality

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 approach reduces the number of processing steps, lowering costs while achieving improved breakdown voltage and on-resistance performance by creating a uniform electric field and optimizing carrier distribution across the transistor.

Implementation Method 1

achieving improved breakdown voltage and on-resistance performance by creating a uniform electric field

Methodology Applied

Scientific EffectElectric Field: Electric Field

Implementation Method 2

optimizing carrier distribution across the transistor

Methodology Applied

Scientific EffectConduction (electrical): Conduction (electrical)

Implementation Method 3

drift region formed into multiple carrier charge zones with varying doping concentrations

Methodology Applied

Scientific EffectDoping: Dopants

Data Source

PatentUS11810976B2Semiconductor device

Publication Date: 2023.11.07 SEMICON COMPONENTS IND LLC

AI summary

In one embodiment, a transistor has a drift region that is formed to have a plurality of zones having different vertical doping profiles across the zones. At least one of the zones has a vertical doping profile that has a first peak near a top surface of the zone and a second peak near a bottom surface. An embodiment may have a lower doping in a region that is between the two peaks.