Ru-Doped InP Current Blocking Layer for Optoelectronic Devices
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Solution Overview
Problem
Conventional current blocking structures in optoelectronic devices suffer from thyristor action and high leakage current at high drive currents and temperatures, limiting their efficiency and suitability for high bit rate modulation due to large parasitic capacitance and inter-diffusion issues with dopants like Fe and Zn.
Innovation Solution
The use of a thinner n-type ruthenium (Ru)-doped indium phosphide (InP) layer with low carrier mobility in current blocking junctions, grown using atmospheric pressure MOVPE with high vapour pressure precursors, reduces leakage current and prevents thyristor breakdown, allowing for effective current blocking without increasing device thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional reverse biased p-n junction current blocking structure is used, then current blocking is achieved, but high leakage current and thyristor action occur at high drive currents and temperatures
Solution Approach 1:
The patent changes the material composition parameter by using Ru-doped InP instead of conventional Fe-doped InP or Zn-doped InP. This material substitution fundamentally alters the electrical properties, achieving low leakage current and preventing thyristor action at high temperatures and drive currents while maintaining effective current blocking
Solution Approach 2:
The patent employs a composite doping approach by combining Ru dopant with InP substrate to create a novel semiconductor material with superior electrical characteristics. This composite material structure enables simultaneous achievement of low capacitance, low leakage current, and high temperature stability
2Object-generated harmful factors
If the n-type semiconductor layer thickness is increased to reduce leakage, then leakage current decreases, but device thickness increases and capacitance increases
Solution Approach 1:
The patent changes the doping concentration parameter of the n-type layer to an optimized range that achieves low leakage current without requiring increased thickness. The Ru-doped InP layer with specific doping concentrations enables effective current blocking at reduced thickness, simultaneously lowering capacitance while maintaining low leakage performance
3Reliability
If Fe and Zn dopants are used in current blocking structures, then current blocking is achieved, but inter-diffusion issues occur between dopants
Solution Approach 1:
The patent changes the dopant identity parameter from Fe or Zn to Ru, which has different diffusion characteristics. This substitution eliminates inter-diffusion issues between dopants while maintaining effective current blocking function, achieving stable dopant distribution throughout device operation
4Productivity
If conventional current blocking structures are used, then device operation is achieved, but high parasitic capacitance limits high bit rate modulation
Solution Approach 1:
The patent changes the material composition parameter to Ru-doped InP, which enables reduced layer thickness while maintaining current blocking effectiveness. This thickness reduction directly decreases parasitic capacitance, enabling high bit rate modulation operation without energy loss limitations
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
The implementation of a thin n-type Ru-InP layer significantly reduces electron travel through the blocking structure, preventing excess leakage and thyristor action, enhancing the efficiency and performance of optoelectronic devices at high temperatures and bit rates.
Implementation Method 1
an unexpectedly low carrier mobility for an n-type material
Implementation Method 2
The lower the capacitance, the higher the speed of the device
Implementation Method 3
Semiconductor devices commonly use the deposition method MOVPE (Metal Organic Vapour Phase Epitaxy)
Implementation Method 4
the holes at the junction material migrate away towards the p-type material whilst the electrons at the junction migrate away towards the n-type material
Implementation Method 5
When electrons and holes combine in a direct band gap semiconductor material, the electrons lose energy and turn from conduction electrons to valence electrons and in the process can emit light
Implementation Method 6
a layer of undoped intrinsic semiconductor material, which is configured to physically separate the semiconductor material arrangement and the first p-type semiconductor material layer
Data Source
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AI summary
The present invention provides a current blocking structure for electronic devices, preferably optoelectronic devices. The current blocking structure comprises a semiconductor material arrangement comprising an n-type ruthenium doped indium phosphide (Ru-InP) layer and a first p-type semiconductor material layer wherein the n-type Ru-InP layer is less than 0.6µm thick. The semiconductor material arrangement and p-type semiconductor material layer form a current blocking p-n junction. The current blocking structure may further comprise other n-type layers and/or multiple n-type Ru-InP layers and/or intrinsic/undoped layers wherein the n-type Ru-InP layers may be thicker than 0.6µm.