Semiconductor Device Non-Overlapping Electrode Layout

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Solution Overview

Problem

The reliability of silicon photonics-based optical modulators is compromised due to dielectric layer damage during manufacturing, leading to short-circuits between semiconductor layers, and the complexity of manufacturing processes increases with protruding n-type semiconductor layers.

Innovation Solution

The design incorporates a first semiconductor layer with a rib section and adjacent slab sections, where the second semiconductor layer covers the rib section's upper and side surfaces, and electrodes are positioned to avoid overlapping with the first semiconductor layer, preventing dielectric layer damage and simplifying manufacturing by forming contact holes without overlapping layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the second semiconductor layer is formed to cover the first semiconductor layer with protruding sections, then the optical modulation performance is improved through better carrier plasma effect, but the manufacturing complexity increases and dielectric layer damage risk increases

Engineering Contradiction:

Improveoptical modulation performanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of having the second semiconductor layer protrude over the first semiconductor layer, the patent inverts the arrangement by positioning the second semiconductor layer and its contact holes such that they do not overlap with the first semiconductor layer in plan view. This eliminates the manufacturing complexity and dielectric layer damage risk while maintaining the optical modulation functionality through the optical waveguide structure.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent divides the structure into distinct non-overlapping regions: the first semiconductor layer forms the optical waveguide core, while the second semiconductor layer is positioned in adjacent regions. The contact holes are segmented to access the second semiconductor layer without penetrating through the first semiconductor layer, thereby separating the manufacturing processes and eliminating the need for complex overlapping alignment.

Inventive Principle:

Principle #1Segmentation

2Reliability

If contact holes are formed through overlapping semiconductor layers, then electrical connection is achieved, but dielectric layer damage occurs leading to short-circuits

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoiddielectric layer damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the second semiconductor layer from the overlapping configuration and positions it in a separate region adjacent to the first semiconductor layer. The contact holes are formed to access only the second semiconductor layer without penetrating the first semiconductor layer, thereby removing the source of dielectric layer damage and short-circuit risks while maintaining electrical connection functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

3Area of stationary object

If the semiconductor layers are arranged in overlapping configuration, then the optical waveguide structure is compact, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvedevice footprintVSAvoidlayer alignment precision

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional overlapping arrangement by positioning the second semiconductor layer and its contact holes in regions that do not overlap with the first semiconductor layer in plan view. This eliminates the need for high-precision overlapping alignment while maintaining a compact device footprint through efficient spatial arrangement of the non-overlapping components.

Inventive Principle:

Principle #13The other way round (Inversion)

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 enhances the reliability and stability of the optical waveguide, reduces power consumption, and simplifies the manufacturing process by preventing short-circuits and dielectric layer damage, while efficiently generating a carrier plasma effect for optical modulation.

Implementation Method 1

an optical waveguide section to propagate light along a first surface of a substrate

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

efficiently generating a carrier plasma effect for optical modulation

Methodology Applied

Scientific EffectCarrier plasma effect: Plasma

Data Source

PatentUS10416382B2Semiconductor device

Publication Date: 2019.09.17 RENESAS ELECTRONICS CORP

AI summary

In an optical waveguide section of an SIS type having a configuration of stacking a second semiconductor layer over a first semiconductor layer with a dielectric layer interposed, the first semiconductor layer is electrically coupled to a first electrode at a first lead-out section where the second semiconductor layer is not stacked. Further, the second semiconductor layer is electrically coupled to a second electrode at a second lead-out section not overlapping with the first semiconductor layer. As a result, when a contact hole for forming the second electrode is formed by dry etching, the dielectric layer between the first semiconductor layer and the second semiconductor layer is not damaged or broken and hence short-circuit failure between the first semiconductor layer and the second semiconductor layer can be prevented. The reliability of the optical waveguide section therefore can be improved.