Semiconductor Transistor Gate Oxide Breakdown Programming

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Solution Overview

Problem

One-time-programmable (OTP) devices in wireless telephones and electronic devices face issues with gate oxide breakdown, leading to over-stressing of transistor source and drain regions, increased leakage current, and malfunction due to variations in breakdown locations, which affect resistance and reading accuracy.

Innovation Solution

A method and apparatus for programming and reading a memory cell using a semiconductor transistor structure with a programmable breakdown condition created between the gate and overlap region, preventing breakdown at the channel region by maintaining a voltage difference below the breakdown voltage, allowing bi-directional sensing and reducing leakage current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a read voltage is applied to detect gate oxide breakdown, then data value can be read, but source and drain regions may be over-stressed causing transistor malfunction and increased leakage current

Engineering Contradiction:
Improveread current detectionVSAvoidtransistor functionality
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an overlap region as an intermediary between the gate and the channel region. This overlap region serves as a mediator that absorbs the breakdown effect, preventing direct stress on the channel region while still enabling readable current flow between gate and source/drain.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the transistor structure into distinct regions: gate, overlap region, and channel region. By spatially separating the breakdown occurrence zone (overlap region) from the critical functional zone (channel region), the patent enables independent optimization of breakdown tolerance and functional reliability.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If breakdown occurs at channel region, then large bipolar resistance is caused, but this requires large read voltage which over-stresses source and drain regions

Engineering Contradiction:
Improvebreakdown detectionVSAvoidread voltage
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The overlap region acts as an intermediary that provides a lower resistance path for current flow compared to channel region breakdown. This mediator enables breakdown detection with smaller read voltages by offering an alternative conduction path that doesn't require high voltage stress.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Use of energy by moving object

If breakdown occurs at source or drain region, then smaller linear resistance is caused, but breakdown location variations affect resistance and reading accuracy

Engineering Contradiction:
Improveread voltageVSAvoidreading accuracy
Core Design Contradiction:
Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent applies local quality by creating distinct electrical characteristics in different regions. The overlap region is specifically engineered to have properties that facilitate breakdown occurrence with low resistance, while the channel region maintains properties suitable for normal transistor operation. This localized differentiation ensures breakdown happens in the desired location with consistent electrical characteristics.

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 leakage current, prevents over-stressing of transistor regions, and allows for lower read voltages, enhancing reliability and power efficiency by maintaining high-speed sensing without requiring channel inversion mode.

Implementation Method 1

An OTP device may program a data value by creating a gate oxide breakdown at a source, drain, and/or channel region of a transistor within the device

Methodology Applied
Scientific EffectGate oxide breakdown: Avalanche Breakdown

Data Source

PatentEP2954531B1System and method of programming a memory cell
Publication Date: 2021.03.17 QUALCOMM INC
  • EP2954531B1 patent drawingFigure 1
  • EP2954531B1 patent drawingFigure 2
  • EP2954531B1 patent drawingFigure 3

AI summary

A method includes creating a breakdown condition at a semiconductor transistor structure that includes an overlap region and a channel region. The breakdown condition is created by causing a first voltage difference between a gate of the semiconductor transistor structure and the overlap region to exceed a breakdown voltage of the semiconductor transistor structure while maintaining a second voltage difference between the gate and the channel region at less than the breakdown voltage.