InGaAs Light-Receiving Element With Low-Barrier Capacitance Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor light-receiving elements, such as photoelectric conversion devices, a large barrier between the light absorbing layer and the capacitance reducing layer can hinder electron detection, leading to a deterioration in response performance.
Innovation Solution
A semiconductor light-receiving element with a lamination structure that includes a light absorbing layer of InGaAs, a first semiconductor layer, a second semiconductor layer forming a PN junction with the light absorbing layer, and a capacitance reducing layer of InP, InGaAsP, InAsP, or AlInGaAs, where the capacitance reducing layer has a higher carrier concentration and a larger band gap than the light absorbing layer, reducing the barrier for electrons and preventing light absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the carrier concentration of the capacitance reducing layer is increased to reduce the electron barrier, then the response performance improves, but the light absorption capability may deteriorate
Solution Approach 1:
The patent applies local quality by creating distinct regions within the capacitance reducing layer with different carrier concentrations. The first region has a higher carrier concentration to reduce electron barrier, while the second region has a lower carrier concentration to minimize light absorption. This spatial differentiation of properties allows simultaneous optimization of both response performance and light absorption characteristics.
Solution Approach 2:
The patent utilizes parameter changes by varying the carrier concentration parameter across different regions of the capacitance reducing layer. By controlling the carrier concentration to be higher in the first region and lower in the second region, the patent achieves both reduced electron barrier and suppressed light absorption, resolving the technical contradiction through parameter optimization.
2Reliability
If the thickness of the capacitance reducing layer is increased to reduce junction capacitance, then the capacitance reduces, but the response speed deteriorates due to increased carrier travel time
Solution Approach 1:
The patent applies local quality by creating regions with different carrier concentrations within the capacitance reducing layer. The higher carrier concentration in the first region facilitates faster electron transport, while the lower carrier concentration in the second region maintains low capacitance. This spatial differentiation allows the layer to simultaneously achieve low capacitance and fast response speed.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a uniform single-parameter optimization to a multi-dimensional approach, varying both carrier concentration and spatial position. By creating a non-uniform carrier concentration profile across the layer thickness, the patent achieves both low capacitance and fast response through dimensional optimization of the carrier distribution.
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 structure suppresses the generation of slow carriers, enhances response speed, and maintains high sensitivity across communication wavelength bands.
Implementation Method 1
a carrier concentration of the capacitance reducing layer is 5×10^15 cm^-3 or less, and is higher than a carrier concentration of the first region of the light absorbing layer
Implementation Method 2
a band gap of the capacitance reducing layer is larger than a band gap of the light absorbing layer. Accordingly, light absorbed in the light absorbing layer is suppressed from being absorbed in the capacitance reducing layer
Implementation Method 3
the other semiconductor layer from among the first semiconductor layer and the second semiconductor layer includes a second region that has a second conductivity type and forms a PN junction with the first region of the light absorbing layer
Implementation Method 4
a light absorbing layer that contains InGaAs
Data Source
AI summary
Provided is a semiconductor light-receiving element including a substrate, a semiconductor lamination portion formed on the substrate, and first and second electrodes electrically connected to the semiconductor lamination portion. The semiconductor lamination portion includes a light absorbing layer that contains InGaAs and includes a first region that has a first conductivity type, a first semiconductor layer located between the substrate and the light absorbing layer, a second semiconductor layer located on a side opposite to the substrate with respect to the light absorbing layer, and a capacitance reducing layer that has the first conductivity type, consists of any one of InP, InGaAsP, InAsP, and AlInGaAs, and is located between one semiconductor layer from among the first semiconductor layer and the second semiconductor layer, and the light absorbing layer.