Light Detection Device Multilayer Band Gap Transition

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Solution Overview

Problem

Conventional light detection devices face challenges in efficiently detecting different wavelength regions due to abrupt energy band gap changes between buffer and light absorption layers, leading to increased current flow resistance and reduced reliability.

Innovation Solution

A multilayer band gap change layer with different energy band gaps is introduced between the buffer and light absorption layers, along with a Schottky layer made of ITO for improved light permeability and a top layer of p-InzGa1-zN to facilitate Schottky characteristics, ensuring accurate reactivity values and high reliability across various wavelength regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single light absorption layer is used, then the device structure is simple, but it cannot detect multiple wavelength regions accurately

Engineering Contradiction:

Improvedetection of multiple wavelength regionsVSAvoiddevice structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The light absorption layer is divided into multiple sub-layers, each with different thicknesses and materials optimized for specific wavelength regions (UV-C, UV-B, UV-A). This segmentation enables the single device to detect multiple wavelength regions simultaneously while maintaining a relatively compact structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the light absorption layer are assigned different properties: the first light absorption layer targets UV-C with specific thickness and material composition, the second light absorption layer targets UV-B with different parameters, and the third light absorption layer targets UV-A. This local differentiation of properties enables wavelength-specific detection within a unified device structure.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If abrupt energy band gap change is used between buffer and light absorption layers, then the fabrication process is simple, but current flow resistance increases

Engineering Contradiction:

Improvefabrication process simplicityVSAvoidcurrent flow resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A band gap change layer is introduced as an intermediary between the buffer layer and the light absorption layer. This intermediate layer provides a gradual transition of the energy band gap, reducing the abrupt change and thereby decreasing current flow resistance while maintaining fabrication simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The energy band gap parameter is changed gradually through the band gap change layer rather than abruptly. By controlling the composition and thickness of this intermediate layer, the patent achieves a progressive parameter transition that reduces electrical resistance while keeping the manufacturing process straightforward.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If Schottky layer is contacted and fixed during wire bonding, then electrical connection is established, but peeling of the Schottky layer occurs due to stress

Engineering Contradiction:

Improvewire bonding capabilityVSAvoidSchottky layer peeling

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A Schottky fixing layer is applied beforehand to the Schottky layer before wire bonding operations. This fixing layer acts as a cushioning element that absorbs and distributes the mechanical stress during wire bonding, preventing the Schottky layer from peeling while still allowing proper electrical connection to be established.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 enhances current flow and crystalline characteristics, preventing peeling of the Schottky layer during wire bonding, thereby improving the reliability and yield of the light detection device while allowing detection of multiple wavelength regions with a single device.

Implementation Method 1

reduces current flow resistance due to an abrupt energy band gap change between a buffer layer and a light absorption layer, through an application of a multilayer band gap change layer having different energy band gaps

Methodology Applied

Scientific EffectEnergy band gap transition:

Implementation Method 2

uses ITO or the like as a Schottky layer to improve permeability of light to be especially detected

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 3

a light absorption layer disposed over the first band gap change layer

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS9812602B2Light detection device

Publication Date: 2017.11.07 SEOUL VIOSYS CO LTD

AI summary

A light detection device includes a substrate, a buffer layer disposed on the substrate, a first band gap change layer disposed on a portion of the buffer layer, a light absorption layer disposed on the first band gap change layer, a Schottky layer disposed on a portion of the light absorption layer, and a first electrode layer disposed on a portion of the Schottky layer.