Display Pixel Structure With Separate Reflector to Prevent Electrical Opens
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Solution Overview
Problem
The challenge in micro display IC chips is the formation of a native oxide layer on the bottom electrode/reflector, which is dielectric and causes electrical isolation, leading to manufacturing yield degradation due to high reactivity with oxygen, while using low reactivity metals with conductive oxide results in poor optical performance.
Innovation Solution
The solution involves a separate bottom electrode and reflector with a coupling structure extending from the bottom electrode to the light emission device, allowing for electrical coupling independent of the reflector, enabling the use of high reflectivity materials with high oxygen reactivity and low reactivity materials that form conductive oxide, preventing electrical opens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high reactivity metals with high reflectivity are used for the bottom electrode/reflector, then optical performance is improved, but manufacturing yield deteriorates due to oxidation forming dielectric native oxide layers causing electrical isolation
Solution Approach 1:
The invention divides the bottom electrode/reflector into two separate components: a bottom electrode made of low reactivity metal (e.g., titanium nitride, tantalum nitride) that forms conductive native oxide, and a reflector made of high reactivity high reflectivity material (e.g., aluminum, silver) that forms dielectric native oxide. This segmentation allows each component to be optimized independently for its specific function without the conflicting requirements of a single material.
Solution Approach 2:
The coupling structure acts as an intermediary element that electrically connects the bottom electrode to the light emission device. It extends alongside the reflector and provides a dedicated electrical pathway that is independent of the reflector's electrical properties, thereby preventing electrical opens caused by oxidation of the high reactivity reflector material.
2Reliability
If low reactivity metals forming conductive oxide are used for the bottom electrode, then manufacturing yield is improved by preventing electrical opens, but optical performance deteriorates due to poor reflectivity
Solution Approach 1:
The invention divides the bottom electrode/reflector into two separate components: a bottom electrode made of low reactivity metal (e.g., titanium nitride, tantalum nitride) that forms conductive native oxide, and a reflector made of high reactivity high reflectivity material (e.g., aluminum, silver) that forms dielectric native oxide. This segmentation allows each component to be optimized independently for its specific function without the conflicting requirements of a single material.
Solution Approach 2:
The reflector serves multiple functions: it provides high reflectivity for optical performance, acts as a physical barrier to oxidation, and serves as a structural element. The coupling structure provides the electrical connection function that the reflector cannot fulfill due to its oxidation-prone nature, allowing the system to achieve both optical and electrical performance.
3Device complexity
If a single integrated bottom electrode/reflector structure is used, then device complexity is reduced, but electrical isolation occurs due to dielectric native oxide formation on high reactivity materials
Solution Approach 1:
The invention divides the bottom electrode/reflector into two separate components: a bottom electrode made of low reactivity metal (e.g., titanium nitride, tantalum nitride) that forms conductive native oxide, and a reflector made of high reactivity high reflectivity material (e.g., aluminum, silver) that forms dielectric native oxide. This segmentation allows each component to be optimized independently for its specific function without the conflicting requirements of a single material.
Solution Approach 2:
The coupling structure acts as an intermediary element that electrically connects the bottom electrode to the light emission device. It extends alongside the reflector and provides a dedicated electrical pathway that is independent of the reflector's electrical properties, thereby preventing electrical opens caused by oxidation of the high reactivity reflector material.
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 optical performance while maintaining high manufacturing yields by preventing oxidation-induced electrical opens, allowing for the use of materials with high reflectivity and low reactivity with oxygen.
Implementation Method 1
a coupling structure extending from the bottom electrode, alongside the reflector, to an interface between the light emission device and the reflector to electrically couple the bottom electrode to the light emission device
Implementation Method 2
a reflector over the interconnect structure and laterally bordering the bottom electrode... a light emission device overlying the reflector
Data Source
AI summary
Various embodiments of the present disclosure are directed towards an integrated circuit (IC) chip comprising a display pixel in which a bottom electrode and a reflector are separate and border. A light emission device overlies the reflector, and a top electrode overlies the light emission device. A coupling structure extends from the bottom electrode, alongside the reflector, to an interface between the light emission device and the reflector to electrically couple the bottom electrode to the light emission device.