HK/MG MTP MOSFET Programming Without Channel Current

Solution Overview

Problem

Metal-oxide semiconductor (MOS) field-effect transistors (MOSFETs) used in programmable switching devices experience a reduction in switching window and endurance due to charge traps formed in the high-k dielectric layer when programmed, leading to unreliable information access.

Innovation Solution

The implementation of a high-k/metal gate (HK/MG) multi-time programmable (MTP) switching device that eliminates switching electrical current during programming by using a switching controller to apply a switching voltage between the gate and source electrodes without generating a channel current, thereby preventing charge traps in the HK dielectric layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a switching voltage is applied to program the MOSFET, then the MOSFET can be programmed to store information, but a charge trap builds up in the HK dielectric layer reducing switching window and endurance

Engineering Contradiction:

ImproveprogrammabilityVSAvoidswitching window and endurance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the electrical parameters during programming by adjusting drain voltage to eliminate channel current flow while maintaining gate-controlled threshold voltage shifts. By modifying the drain voltage parameter to match the source voltage, the invention prevents charge trap formation while still achieving programmability through threshold voltage modulation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful effect of switching electrical current (which causes charge traps) into a beneficial approach by deliberately eliminating the current flow during programming. The invention uses a programming method that applies voltage without current, transforming the harmful current-induced charge trap mechanism into a current-free programming process that preserves device reliability.

Inventive Principle:

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

2Adaptability or versatility

If a switching electrical current flows during programming, then the MOSFET can be programmed, but charge traps are generated in the HK dielectric layer

Engineering Contradiction:

ImproveprogrammabilityVSAvoidcharge trap formation

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the harmful electrical current component from the programming process. By setting the drain voltage equal to the source voltage, the invention eliminates channel current flow while maintaining the necessary voltage conditions for threshold voltage modulation, thereby separating the useful voltage effect from the harmful current effect.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful effect of switching electrical current (which causes charge traps) into a beneficial approach by deliberately eliminating the current flow during programming. The invention uses a programming method that applies voltage without current, transforming the harmful current-induced charge trap mechanism into a current-free programming process that preserves device reliability.

Inventive Principle:

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

3Loss of information

If conventional programming is used, then information can be stored, but the switching window and endurance are reduced leading to unreliable information access

Engineering Contradiction:

Improveinformation storage capabilityVSAvoidinformation access reliability

Core Design Contradiction:

Loss of informationVSReliability

Solution Approach 1:

The patent changes the electrical parameters during programming by adjusting drain voltage to eliminate channel current flow while maintaining gate-controlled threshold voltage shifts. By modifying the drain voltage parameter to match the source voltage, the invention prevents charge trap formation while still achieving programmability through threshold voltage modulation.

Inventive Principle:

Principle #35Parameter changes

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 restores the switching window and endurance of the MOSFET, ensuring more reliable information access by preventing charge trap buildup during programming and erasing processes.

Implementation Method 1

a charge trap may build up in an HK dielectric layer/interface layer of the MTP MOSFET due to a switching electrical current induced by the applied switching voltage

Methodology Applied

Scientific EffectCharge trapping: Electrical Accumulator

Implementation Method 2

When the switching voltage (VGS) 32 is greater than or equal to the threshold voltage (VT) of the nMOSFET 10, the nMOSFET 10 switches into an inversion mode, and the channel region 36 becomes conductive

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9413349B1High-K (HK)/metal gate (MG) (HK/MG) multi-time programmable (MTP) switching devices, and related systems and methods

Publication Date: 2016.08.09 QUALCOMM INC

AI summary

Aspects disclosed in the detailed description include high-k (HK)/metal gate (MG) (HK/MG) multi-time programmable (MTP) switching devices, and related systems and methods. One type of HK/MG MTP switching device is an MTP metal-oxide semiconductor (MOS) field-effect transistor (MOSFET). When the MTP MOSFET is programmed, a charge trap may build up in the MTP MOSFET due to a switching electrical current induced by a switching voltage. The charge trap reduces the switching window and endurance of the MTP MOSFET, thus reducing reliability in accessing the information stored in the MTP MOSFET. In this regard, an HK/MG MTP switching device comprising the MTP MOSFET is configured to eliminate the switching electrical current when the MTP MOSFET is programmed. By eliminating the switching electrical current, it is possible to avoid a charge trap in the MTP MOSFET, thus restoring the switching window and endurance of the MTP MOSFET for reliable information access.