Optoelectronic Device Pixel Definition via Transfer and Trenching
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Solution Overview
Problem
The existing manufacturing methods for optoelectronic devices, such as gallium nitride LED arrays, face challenges in achieving high alignment accuracy during assembly, particularly as pixel pitch decreases, limiting resolution and integration density.
Innovation Solution
The method involves forming an active diode stack and an integrated control circuit with MOS transistors, then transferring the control circuit onto the diode stack, where trenches are formed to delimit pixels, allowing for improved alignment accuracy and separate metallizations for each pixel, enabling high-resolution pixel formation without stringent initial alignment requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the control circuit and LED array are separately manufactured and then hybridized by stacking, then the device can be assembled with modular components, but the alignment accuracy deteriorates when pixel pitch decreases
Solution Approach 1:
The control circuit is formed on the same substrate as the LED array before final assembly, with metal pads pre-positioned and connected to corresponding LEDs. This preliminary integration eliminates the need for high-precision alignment during stacking, as the components are already in their correct relative positions
Solution Approach 2:
The control circuit and LED array are merged into a single integrated structure on the same substrate, rather than being separate modules. This combining allows direct connection between control circuit metal pads and LED contacts, eliminating alignment issues between separate components
2Device complexity
If the positions of LEDs and control circuit components are defined before transfer, then the device structure is well-defined, but the alignment accuracy deteriorates during substrate transfer
Solution Approach 1:
The control circuit components and metal pads are formed on the substrate before the LED array is transferred and positioned. This preliminary formation allows the LED positions to be defined relative to the already-present control circuit, ensuring accurate alignment without requiring high-precision alignment during the transfer process
Solution Approach 2:
Instead of transferring the control circuit onto the LED array, the LED array is transferred onto the substrate that already contains the control circuit. This inversion of the transfer sequence allows the control circuit to serve as the reference structure, simplifying alignment
3Manufacturing precision
If high alignment accuracy is required during assembly, then the pixel resolution can be maintained, but the manufacturing complexity and difficulty increase
Solution Approach 1:
The control circuit is fabricated with precise dimensions and positions using standard integrated circuit manufacturing methods before the LED array is transferred. This preliminary precision work is performed when the substrate is accessible and can be easily processed, avoiding the need for complex alignment procedures during final assembly
Solution Approach 2:
A common substrate serves as an intermediary platform that holds both the control circuit and the LED array in their correct relative positions. This substrate acts as a reference frame that simplifies the assembly process, as components only need to be positioned relative to the substrate rather than to each other with high precision
Data Source
AI summary
An optoelectronic device manufacturing method including the steps of: a) forming an active diode stack including first and second of opposite conductivity types; b) forming an integrated control circuit including a plurality of elementary control cells each including at least one MOS transistor; c) after steps a) and b), transferring the integrated control circuit onto the upper surface of the active diode stack; and d) after step c), forming trenches extending vertically through the integrated control circuit and emerging into or onto the first layer and delimiting a plurality of pixels each including a diode and an elementary control cell.