MIS Edge Structure for Microdevice Leakage Current Control
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Solution Overview
Problem
The reduction in size of optoelectronic devices, such as LEDs, leads to performance issues like higher leakage current, charge crowding, and non-radiative recombination due to defects and material limitations, which are not effectively addressed by existing technologies.
Innovation Solution
The implementation of a Metal-Insulator-Semiconductor (MIS) structure on the edges of microdevices to modulate the internal electric field, reduce leakage current, and control charge transition and accumulation, combined with conductivity modulation techniques to manage lateral current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of optoelectronic devices is reduced to increase pixel density, then the number of devices per wafer area increases, but device performance deteriorates due to higher leakage current, charge crowding, and non-radiative recombination
Solution Approach 1:
The patent applies local quality by implementing MIS structures specifically at the edges and perimeters of microdevice regions, rather than uniformly across the entire device. This localized approach addresses the specific problem of leakage current and charge crowding at device boundaries while maintaining the reduced device size needed for high pixel density. The edge-specific treatment allows different regions of the device to have optimized properties for their specific functional requirements.
2Loss of substance
If the size of optoelectronic devices is reduced, then material utilization improves, but leakage current increases due to defects and material limitations
Solution Approach 1:
The patent introduces MIS structures as intermediary elements at the device edges, which act as mediators to control and modulate the electric field. These intermediary structures prevent direct harmful interactions between adjacent microdevices and reduce leakage current by establishing controlled transition zones. The MIS structures serve as buffer regions that mitigate the harmful effects of size reduction while preserving material utilization efficiency.
3Ease of manufacture
If conventional bonding methods are used to transfer device layers to system substrate, then device integration is achieved, but charge imbalance and unwanted recombination occur
Solution Approach 1:
The patent implements preliminary action by forming MIS structures on the device layers before the bonding and transfer process to the system substrate. This pre-treatment prepares the device edges in advance to prevent charge imbalance and unwanted recombination during subsequent processing steps. By addressing potential problems before they occur, the preliminary MIS structure formation ensures better charge balance is maintained throughout the integration process.
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 approach enhances the performance of optoelectronic devices by reducing leakage current, improving charge balance, and increasing the number of devices per wafer area, resulting in higher resolution and brightness for LED displays while lowering fabrication costs.
Implementation Method 1
to modulate the internal electric field, reduce leakage current, and control charge transition and accumulation
Implementation Method 2
to modulate the internal electric field, reduce leakage current
Implementation Method 3
combined with conductivity modulation techniques to manage lateral current flow
Data Source
AI summary
A microdevice structure comprising at least part of an edge of a microdevice is covered with a metal-insulator-semiconductor (MIS) structure, wherein the MIS structure comprises a MIS dielectric layer and a MIS gate conductive layer, at least one gate pad provided to the MIS gate conductive layer, and at least one micro device contact extended upwardly on a top surface of the micro device.