Monolithic Nanophotonic Device on Semiconductor Substrate

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing semiconductor technologies face challenges in achieving high-performance, stable photonic light emitting devices on Si substrates due to defects, high threshold current, high energy consumption, and low modulation speed, as well as incompatibility with CMOS devices in monolithic integration.

Innovation Solution

A photonic light generating device is integrated on a semiconductor substrate using a second semiconductor material with a different lattice constant, grown in a via opening surrounded by a dielectric and waveguide core material stack, which enables high modulation speed without high energy consumption and is free of crystallographic defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If photonic light emitting devices are integrated on Si substrate using prior art monolithic integration, then integration with electronic devices is achieved, but the devices exhibit large number of defects, high threshold current, high energy consumption, and low modulation speed

Engineering Contradiction:

Improveintegration compatibilityVSAvoiddevice performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The device is segmented into distinct functional regions: a SiGe buffer layer for lattice matching, a III-V semiconductor active region for light emission, and Si-based waveguide and electronic device regions. This segmentation allows each region to be optimized independently, achieving both high performance and compatibility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A SiGe buffer layer is introduced as an intermediary between the Si substrate and the III-V semiconductor active region. This intermediate layer gradually transitions the lattice constant, reducing misfit dislocations and enabling high-quality III-V growth on Si substrate without compromising device performance

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If photonic light emitting devices are provided with high modulation speed, then communication performance is improved, but energy consumption increases

Engineering Contradiction:

Improvemodulation speedVSAvoidenergy consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The device utilizes quantum confined Stark effect (QCSE) in quantum well structures to achieve high modulation speed through electric field-induced refractive index changes. The parameter optimization of quantum well thickness and composition enables fast modulation with reduced drive current, lowering energy consumption while maintaining high speed performance

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If second semiconductor material with different lattice constant is grown on first semiconductor material, then photonic light generating capability is achieved, but crystallographic defects occur due to lattice mismatch

Engineering Contradiction:

Improvephotonic light generating capabilityVSAvoidcrystallographic quality

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The device structure employs local quality optimization by using SiGe buffer layers with gradually increasing Ge content in stepped regions. Each local region has optimized composition to match the underlying layer's lattice constant, minimizing misfit dislocations while enabling III-V growth. The active region is further optimized with composition gradients to maintain crystallographic quality throughout the heterostructure

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

The solution provides a stable and high-performance photonic light emitting device that is compatible with CMOS devices, overcoming previous limitations of defects, energy consumption, and modulation speed, while allowing for integration with electronic and other photonic devices on the same substrate.

Implementation Method 1

a second semiconductor material having a second lattice constant that differs from the first lattice constant and that is capable of generating and emitting light

Methodology Applied

Scientific EffectLight emission: Electroluminescence

Implementation Method 2

The via opening exposes a surface of the first semiconductor material

Methodology Applied

Scientific EffectEtching:

Data Source

PatentUS9917414B2Monolithic nanophotonic device on a semiconductor substrate

Publication Date: 2018.03.13 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A photonic light generating device is provided on a portion of a first semiconductor material. The photonic light generating device includes a second semiconductor material that has a different lattice constant than the lattice constant of the first semiconductor material and that is capable of generating and emitting light. The second semiconductor material of the photonic light generating device is present in a via opening that is provided into a waveguide core material and an underlying dielectric material. The via opening exposes a surface of the first semiconductor material.