Leak Current Suppression in Semiconductor Laser Diodes
Here’s PatSnap Eureka !
Summary
Problems
Conventional semiconductor laser diodes with a ridge-waveguide structure suffer from significant leak current issues in the window region, particularly for short cavity type lasers, which degrade laser characteristics and make low-current operation challenging.
Innovation solutions
The introduction of a semiconductor layer with a band gap larger than the laser beam's energy, composed of a stacked structure of n-type, semi-insulating, and p-type layers, where materials like Ru, Os, Rh, and Ti are doped to create high resistivity, reducing leak current by suppressing interdiffusion with Zn, thereby enhancing the resistivity of the window region.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If Fe-doped semi-insulating layers are used in the window region, then resistivity increases and leak current is suppressed, but interdiffusion between Fe and Zn dopants reduces the effectiveness of leak current suppression
Why choose this principle:
The patent introduces an undoped InP layer as an intermediary barrier between the Fe-doped semi-insulating layer and the Zn-doped p-type cladding layer. This intermediary layer prevents direct interdiffusion between Fe and Zn dopants, maintaining the stability of both doping concentrations while preserving the high resistivity needed for leak current suppression.
Principle concept:
If Fe-doped semi-insulating layers are used in the window region, then resistivity increases and leak current is suppressed, but interdiffusion between Fe and Zn dopants reduces the effectiveness of leak current suppression
Why choose this principle:
The window region structure is segmented into multiple distinct layers: Fe-doped semi-insulating layer, undoped InP barrier layer, and Zn-doped p-type cladding layer. This segmentation physically separates the dopant sources and prevents their interdiffusion, allowing each layer to maintain its intended electrical properties independently.
Application Domain
Data Source
AI summary:
The introduction of a semiconductor layer with a band gap larger than the laser beam's energy, composed of a stacked structure of n-type, semi-insulating, and p-type layers, where materials like Ru, Os, Rh, and Ti are doped to create high resistivity, reducing leak current by suppressing interdiffusion with Zn, thereby enhancing the resistivity of the window region.
Abstract
In an edge emitting laser having a window region with a ridge-waveguide structure, particularly, in a short cavity type of a laser operated with a low current, there has been a problem of its operating current being increased due to current leakage of the window portion. To solve this problem, in the window region, between an n-type substrate and a p-type cladding layer, a semi-insulating semiconductor layer into which Ru is doped is inserted. Alternatively, a stacked structure of a Ru-doped layer and a Fe-doped layer is introduced.