High Resistivity Substrate RF Noise Reduction

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Solution Overview

Problem

The high cost of manufacturing RF front-end modules (FEM) due to the expensive SOI substrate and SIP/MCM process limits the reduction of manufacturing costs, and existing RF modules face challenges in reducing RF noise coupling and improving electrical characteristics.

Innovation Solution

A semiconductor device is developed using a high resistivity silicon substrate with a deep trench device isolation region and a low concentration well region to surround transistors, which includes a gate structure, source and drain regions, and high concentration impurity regions, reducing RF noise coupling and improving electrical characteristics by extending depletion regions and reducing junction capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If SOI substrate is used to reduce RF noise coupling, then RF noise coupling is reduced, but manufacturing cost increases

Engineering Contradiction:

ImproveRF noise couplingVSAvoidmanufacturing cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent replaces expensive SOI substrates with conventional low-resistivity silicon substrates, using a cost-effective alternative material that achieves the same RF noise reduction function through different structural mechanisms (deep trench isolation and deep well regions instead of buried oxide layer)

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the substrate resistivity parameter from high-resistivity (SOI) to conventional low-resistivity silicon, and compensates by adjusting other parameters such as increasing trench depth and creating deep well regions to achieve equivalent or superior RF noise coupling reduction

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If SIP/MCM process is used for RF module manufacturing, then device integration is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvedevice integrationVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent creates a universal fabrication process that works with conventional silicon substrates, allowing the same manufacturing steps to produce both standard digital devices and RF devices, thereby eliminating the need for specialized SIP/MCM processes while maintaining integration capabilities

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges RF device fabrication with standard CMOS digital device fabrication processes, combining previously separate manufacturing flows into a single unified process that produces both device types on the same substrate using identical fabrication steps

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If deep trench device isolation region is formed deeper than deep well region, then RF noise coupling is reduced, but device complexity increases

Engineering Contradiction:

ImproveRF noise couplingVSAvoiddevice structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the device isolation into two distinct parts: deep trench isolation extending through the substrate and shallow trench isolation at the surface level. This segmentation allows each trench type to perform its specific function optimally while maintaining overall structural simplicity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extends the deep trench isolation into the vertical dimension, making it deeper than the deep well region, thereby utilizing the depth dimension to achieve RF noise reduction without increasing lateral structural complexity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 solution significantly reduces RF noise coupling and manufacturing costs, enhances RF switch performance by lowering off-state capacitance and on-state resistance, and improves heat dissipation efficiency, making it suitable for use in RF modules.

Implementation Method 1

extending depletion regions and reducing junction capacitance

Methodology Applied

Scientific EffectDepletion region extension: Electric Field

Implementation Method 2

reducing junction capacitance

Methodology Applied

Scientific EffectJunction capacitance reduction: Capacitance

Implementation Method 3

improves heat dissipation efficiency

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10325867B2Semiconductor device and radio frequency module formed on high resistivity substrate

Publication Date: 2019.06.18 DONGBU HITEK CO LTD

AI summary

A semiconductor device includes a high resistivity substrate, a transistor formed on the high resistivity substrate, and a deep trench device isolation region formed in the high resistivity substrate to surround the transistor. Particularly, the high resistivity substrate has a first conductive type, and a deep well region having a second conductive type is formed in the high resistivity substrate. Further, a low concentration well region having the first conductive type is formed on the deep well region, and the transistor is formed on the low concentration well region.