Micro LED Groove and Schottky Isolation for Pixel Crosstalk
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Solution Overview
Problem
Micro LED structures face issues with electrical current crosstalk and optical crosstalk due to interconnected light-emitting layers, leading to unstable operation and reduced light intensity, which complicates manufacturing and increases costs.
Innovation Solution
The micro LED structures incorporate a continuous quantum well interconnected across pixels, with a specially designed structure featuring grooves and sub-grooves to mitigate electrical current crosstalk and optical crosstalk, using a high-work-function metal layer to form Schottky contacts and create depletion regions, and double-slit diffraction to isolate light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the micro LED size is reduced to achieve higher pixel density, then the pixel density is improved, but the efficiency and carrier lifetime degrade due to surface recombination and poor p-type conduction
Solution Approach 1:
The top epitaxial layer is divided into an array of micro LEDs by forming grooves that segment the continuous layer into discrete pixel regions, allowing each micro LED to maintain proper electrical characteristics while achieving high pixel density through the segmented array structure
Solution Approach 2:
The groove structure creates localized regions with different properties: the groove walls provide isolation for electrical current while the groove geometry (including sub-grooves) controls optical emission patterns, enabling simultaneous achievement of high density and reliable operation through localized structural modifications
2Reliability
If a conventional isolation structure is formed around each micro LED to prevent crosstalk, then the crosstalk is reduced, but the volume of the micro LED increases and integration is decreased
Solution Approach 1:
The groove structure serves dual functions by simultaneously providing electrical isolation to prevent current crosstalk and optical isolation to prevent light crosstalk, eliminating the need for separate isolation structures and reducing overall device volume
Solution Approach 2:
The groove structure acts as a multi-functional element that provides both electrical isolation (preventing carrier flow between pixels) and optical isolation (preventing light leakage between pixels), thereby preventing crosstalk while minimizing volume increase
3Reliability
If the isolation structure is formed high enough to isolate light crosstalk, then the optical crosstalk is prevented, but the volume of the micro LED increases further
Solution Approach 1:
The groove structure utilizes the vertical dimension by extending grooves through the epitaxial layer depth, creating effective optical isolation through the groove geometry and material properties rather than relying solely on increased lateral dimensions, thus preventing optical crosstalk while minimizing volume increase
4Illumination intensity
If extra reflective structures are configured around the mesa to realize directional emission, then the directional emission is achieved, but the manufacturing process becomes complex and cost increases
Solution Approach 1:
The groove structure combines multiple functions including isolation and directional emission control into a single structural feature, eliminating the need for separate reflective structures and simplifying the manufacturing process while maintaining directional emission capability
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 solution effectively prevents electrical current crosstalk and optical crosstalk, enhancing the well plug effect and light-extraction efficiency, while maintaining high performance and reducing manufacturing complexity and costs.
Implementation Method 1
using a high-work-function metal layer to form Schottky contacts and create depletion regions
Implementation Method 2
using a high-work-function metal layer to form Schottky contacts and create depletion regions
Implementation Method 3
double-slit diffraction to isolate light emission
Data Source
AI summary
An exemplary micro light-emitting diode (LED) structure includes: a bottom epitaxial layer of a first conductive type; a light-emitting layer, formed on the bottom epitaxial layer; and a top epitaxial layer of a second conductive type. The top epitaxial layer is formed on the light-emitting layer and comprises an array of first grooves dividing the top epitaxial layer into an array of micro LEDs. Each of the first grooves comprises a first sub-groove.