Vertical Current Flow in Semiconductor Light Emitting Devices
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Solution Overview
Problem
Semiconductor light emitting devices suffer from reduced luminous efficiency due to current crowding, where electric current flows horizontally across the active layer, leading to uneven current distribution.
Innovation Solution
The semiconductor light emitting device is designed with a through hole and a contact layer connected to the first conductive semiconductor layer, allowing electric current to flow vertically, reducing current crowding and enhancing luminous efficiency through the use of a side wall insulating film and a transparent electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electric current flows horizontally across the active layer, then the device structure is simple, but current crowding occurs and luminous efficiency is reduced
Solution Approach 1:
The patent introduces a vertical current flow path through the active layer by creating through-holes that extend from the first surface to the second surface. This dimensional change from horizontal to vertical current flow enables uniform current distribution throughout the active layer, eliminating current crowding and improving luminous efficiency without significantly complicating the overall device structure
2Device complexity
If current crowding occurs in the active layer, then the device structure remains simple, but luminous efficiency is reduced
Solution Approach 1:
The invention transforms the current flow from a two-dimensional horizontal path to a three-dimensional vertical path through the active layer. The through-holes create multiple vertical current channels that distribute current uniformly across the active layer, thereby improving luminous efficiency (productivity) while maintaining relatively simple device structure
Solution Approach 2:
The active layer is segmented into multiple regions through the creation of through-holes, allowing current to flow through distinct vertical pathways. This segmentation prevents current crowding by distributing the total current across multiple separated channels, thereby improving luminous efficiency without requiring complex overall device architecture
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 configuration improves luminous efficiency by ensuring a more even current distribution and reduces light absorption, resulting in increased light extraction efficiency.
Implementation Method 1
a contact layer connected to the first conductive semiconductor layer, disposed in the through hole, and disposed through the semiconductor stack
Implementation Method 2
a side wall insulating film disposed on a side wall of the through hole to insulate the contact layer from the second conductive semiconductor layer and the active layer
Data Source
AI summary
A semiconductor light emitting device includes a semiconductor stack including a first conductive semiconductor layer including a first surface, a second conductive semiconductor layer including a second surface opposite to the first surface, an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer, and a through hole disposed through the semiconductor stack. The semiconductor light emitting device further includes a contact layer connected to the first conductive semiconductor layer, disposed in the through hole, and disposed through the semiconductor stack, a first electrode layer connected to the contact layer, and a second electrode layer disposed on the second surface, and including a pad forming portion on which the semiconductor stack is not disposed. The semiconductor light emitting device further includes an insulating layer disposed between the first electrode layer and the second electrode layer, and an electrode pad disposed on the pad forming portion.