Back-Gate Diode Temperature Sensing in FDSOI RF Power Amplifiers

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Solution Overview

Problem

High frequency RF power amplifiers generate excessive heat, leading to performance degradation and potential overheating issues, which existing technologies fail to effectively monitor and manage without impacting device design or requiring additional costly components.

Innovation Solution

A built-in temperature sensor structure utilizing a back-gate diode on a fully depleted semiconductor on insulator (FDSOI) substrate, integrated with temperature sensing circuitry, allows for in-situ temperature monitoring without additional masks or significant design changes, using established IC technology for fabrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high current density is used to operate RF power amplifiers at high frequency, then amplification performance is improved, but heat generation increases causing device overheating

Engineering Contradiction:
Improveamplification powerVSAvoiddevice temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent implements a temperature sensing circuit that continuously monitors the temperature of the RF power amplifier through a back-gate diode and provides feedback signals. This feedback mechanism enables real-time temperature monitoring and allows the system to adjust operating parameters or activate cooling mechanisms when temperature thresholds are exceeded, thus resolving the contradiction between maintaining high power output and preventing overheating.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If additional temperature monitoring components are added to the RF power amplifier, then temperature monitoring capability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvetemperature measurement capabilityVSAvoiddevice structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent utilizes the back-gate diode, which is an existing component in FDSOI-based RF power amplifiers, for dual purposes: its original function in device operation and as a temperature sensor. By making the back-gate diode multi-functional, the patent achieves temperature monitoring capability without adding separate dedicated temperature sensing components, thus improving measurement capability while maintaining device simplicity and reducing manufacturing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The temperature sensing circuit is integrated within the RF power amplifier itself, using the device's own back-gate diode as the sensing element. This self-service approach eliminates the need for external temperature monitoring components and reduces overall device complexity, as the amplifier monitors its own temperature using its inherent structure.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If conventional temperature sensing methods are used in RF power amplifiers, then temperature monitoring is achieved, but manufacturing cost increases due to additional masks and design modifications

Engineering Contradiction:
Improvetemperature sensing accuracyVSAvoidmanufacturing process simplicity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent leverages the back-gate diode already present in FDSOI RF power amplifier designs for temperature sensing purposes. Since this diode is part of the standard device architecture, no additional masks or design modifications are required during manufacturing. The same fabrication process that creates the functional amplifier also creates the temperature sensing capability, thereby maintaining ease of manufacture while achieving accurate temperature sensing.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables cost-effective, non-intrusive temperature monitoring and management in RF/mmW power amplifiers, maintaining device performance by detecting temperature changes and providing feedback for cooling adjustments, thus preventing overheating.

Implementation Method 1

detecting a current at the back-gate diode during the biasing; and converting the current to a temperature reading of the heat generating device

Methodology Applied
Scientific EffectTemperature-dependent current characteristics of diode: Diode

Data Source

PatentEP4328961B1Built-in temperature sensors
Publication Date: 2024.11.13 GLOBALFOUNDRIES US INC
  • EP4328961B1 patent drawingFigure 1
  • EP4328961B1 patent drawingFigure 2A
  • EP4328961B1 patent drawingFigure 2B

AI summary

The present disclosure relates to semiconductor structures and, more particularly, to built-in temperature sensors and methods of manufacture and operation. The structure includes: a semiconductor on insulator substrate; an insulator layer under the semiconductor on insulator substrate; a handle substrate under insulator layer; a first well of a first dopant type in the handle substrate; a second well of a second dopant type in the handle substrate, adjacent to the first well; and a back-gate diode at a juncture of the first well and the second well.