Charge-Balanced Channel Diode for High Voltage and Fast Recovery

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Solution Overview

Problem

Conventional PN diodes have a long recovery time and high power loss due to their operation mechanism, which is inefficient for high voltage and high frequency applications compared to channel diodes, but channel diodes face limitations in supporting high voltages and have series resistance issues that affect performance.

Innovation Solution

The development of a charge-balanced channel diode structure with a drift region and an electrode shield that balances charge, allowing for higher voltage support and reduced series resistance, enabling faster recovery times and lower power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional PN diode structure is used, then the device can support high voltage, but the recovery time is long and power loss is high

Engineering Contradiction:

Improverecovery timeVSAvoidpower loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The diode is segmented into two functional parts: a PN junction for voltage support and a MOSFET for current conduction. This segmentation allows each component to optimize its function - the PN junction handles high voltage blocking while the MOSFET provides low-resistance current path, eliminating the trade-off between recovery time and power loss in conventional PN diodes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a single PN junction structure that must compromise between conduction resistance and recovery time, the invention inverts the approach by using a MOSFET (majority carrier device with fast recovery) in parallel with a PN diode, where the MOSFET's channel conducts current during forward bias, effectively reversing the traditional reliance on minority carrier diffusion

Inventive Principle:

Principle #13The other way round (Inversion)

2Loss of energy

If a channel diode structure is used to reduce power loss and recovery time, then the device achieves faster switching and lower power consumption, but the voltage support capability is limited

Engineering Contradiction:

Improvepower lossVSAvoidvoltage support capability

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The invention merges a PN diode and a MOSFET into a single integrated structure where both components share common regions (source/body diffusion, drain/PN junction). This merging allows the device to combine the high voltage capability of the PN junction with the low conduction loss and fast recovery of the MOSFET channel, achieving both objectives simultaneously

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The channel diode structure uses a composite configuration combining two different semiconductor device types (PN diode and MOSFET) with complementary characteristics. The PN junction provides high voltage blocking while the MOSFET channel provides low-resistance conduction, creating a composite device that exceeds the capabilities of either component alone

Inventive Principle:

Principle #40Composite materials

3Loss of time

If a channel diode structure is used, then the recovery time is reduced, but series resistance increases affecting performance

Engineering Contradiction:

Improverecovery timeVSAvoidseries resistance

Core Design Contradiction:

Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The device exhibits different conduction mechanisms in different regions: the MOSFET channel provides low-resistance path in the central region during forward conduction, while the PN junction handles voltage blocking at the boundaries. This local quality optimization minimizes series resistance where current flows while maintaining voltage support capability where needed

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

The charge-balanced channel diode structure supports higher voltages with reduced power loss and faster recovery times, improving performance in high frequency and high voltage applications while minimizing series resistance and operational power.

Implementation Method 1

a charge-balanced channel diode structure with a drift region and an electrode shield that balances charge

Methodology Applied

Scientific EffectCharge balancing:

Implementation Method 2

When the body potential of transistor 3000 begins to rise the source to body offset voltage is reduced and the turn on voltage of transistor 3000 is lowered due to the body effect

Methodology Applied

Scientific EffectBody effect:

Data Source

PatentUS8294210B2High voltage channel diode

Publication Date: 2012.10.23 TEXAS INSTRUMENTS INC

AI summary

A channel diode structure having a drift region and method of forming. A charge balanced channel diode structure having an electrode shield and method of forming.