LED Chip Passivation with Magnesium Oxide and Nitride
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Solution Overview
Problem
Light-emitting diode chips, particularly those based on InGaAlP, suffer from low efficiency due to nonradiative recombinations of charge carriers on etched side surfaces caused by oxygen bonding, leading to intermediate states in the band gap that reduce radiation generation.
Innovation Solution
A passivation layer consisting of magnesium oxide and magnesium nitride is applied to the side surfaces of the epitaxial semiconductor layer sequence, replacing oxygen bonds and promoting nitridation, which reduces intermediate states and enhances radiative recombination by forming indium-nitrogen, aluminum-nitrogen, and gallium-nitrogen bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the side surfaces of the epitaxial semiconductor layer sequence are etched, then the shape and structure of the light-emitting diode chip can be defined, but nonradiative recombinations of charge carriers occur on the etched side surfaces due to oxygen bonding, reducing efficiency
Solution Approach 1:
A passivation layer is introduced as an intermediary between the etched side surfaces and the environment. This passivation layer prevents oxygen from bonding to the semiconductor material at the side surfaces, thereby eliminating the harmful intermediate states in the band gap that cause nonradiative recombination, while allowing the etched shape to be maintained
Solution Approach 2:
The passivation layer creates an inert protective environment around the semiconductor side surfaces, isolating them from oxygen in the surrounding atmosphere. This prevents oxidation and the formation of intermediate states that would otherwise lead to energy loss through nonradiative recombination
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 significantly increases the efficiency of light-emitting diode chips, especially those with small lateral extent, by minimizing nonradiative recombinations and maximizing radiative recombination, thereby enhancing radiation output.
Implementation Method 1
bonds with nitrogen are formed on the interface with the epitaxial semiconductor layer sequence instead of the bonds of the compound semiconductor material with oxygen
Implementation Method 2
the radiative recombination of charge carriers in the active zone is increased and the efficiency of the light-emitting diode chip is thus increased
Implementation Method 3
Since magnesium has a higher affinity for oxygen than the elements contained in the compound semiconductor material, exchange of oxygen and nitrogen takes place and bonds with nitrogen are formed on the interface with the epitaxial semiconductor layer sequence
Implementation Method 4
the compound semiconductor material is oxidized in the region of the side surface of the semiconductor layer sequence
Data Source
AI summary
A light-emitting diode chip that includes an epitaxial semiconductor layer sequence having an active region that generates electromagnetic radiation during operation, and a passivation layer comprising magnesium oxide and magnesium nitride. The passivation layer may be applied to a lateral surface of the semiconductor layer sequence, and the passivation layer covering at least the active region.