MOSFET Drain Current Enhancement via Inherent BJT Activation

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Solution Overview

Problem

Conventional MOSFETs are designed to nullify the effect of the inherent bipolar junction transistor (BJT), which limits the enhancement of MOSFET performance.

Innovation Solution

A method to increase on-state drain current by utilizing the inherent BJT, achieved by applying specific voltage and current conditions to the gate, drain, source, buried layer, and body of a semiconductor device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional MOSFET manufacturing process and operation scheme are used, then the inherent BJT effect is nullified, but the drain current is limited

Engineering Contradiction:

Improvedrain currentVSAvoidinherent BJT effect

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful inherent BJT effect into a beneficial component by applying specific voltage conditions (Vgs > Vt + Vbe) to activate the BJT's current amplification capability. The BJT's base-collector junction is forward-biased and emitter-collector junction is reverse-biased, transforming the previously detrimental parasitic BJT into a useful current enhancement mechanism that increases drain current without requiring additional external components.

Inventive Principle:

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

2Power

If voltage and current conditions are applied to activate inherent BJT, then current flow from drain to source increases, but device complexity increases

Engineering Contradiction:

Improvecurrent flow from drain to sourceVSAvoidvoltage and current control conditions

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent implements self-service by utilizing the MOSFET's own inherent BJT structure to provide current amplification. The BJT is automatically activated when the MOSFET operates in the saturation region with appropriate gate voltage, eliminating the need for separate external BJT components or complex additional control circuits. The device's existing structure serves dual purposes: MOSFET switching and BJT current amplification.

Inventive Principle:

Principle #25Self-service

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 method enhances current flow from the drain to the source, increasing write current in non-volatile memory cells and improving MOSFET performance without altering the off-state drain current.

Implementation Method 1

Because PN junctions are created in the source-to-channel and the drain-to-channel of a metal-oxide-semiconductor field-effect transistor (MOSFET), a bipolar junction transistor (BJT) is inherently formed during manufacture of the MOSFET

Methodology Applied

Scientific EffectBipolar junction transistor effect:

Implementation Method 2

a gate positioned in between the source region and the drain region

Methodology Applied

Scientific EffectField effect transistor conduction:

Implementation Method 3

applying a positive voltage to the body lowers a threshold voltage of the semiconductor device

Methodology Applied

Scientific EffectBody effect: Electric Field

Data Source

PatentUS20250104768A1A Semiconductor Device

Publication Date: 2025.03.27 ZENO SEMICONDUCTOR INC

AI summary

Methods and devices for increasing the on-state drain current of semiconductor devices.