III-V Semiconductor Stacked Body Carrier Accumulation
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Solution Overview
Problem
The sensitivity of infrared light-receiving devices is compromised due to carrier accumulation at the interface between the diffusion blocking layer and the light-receiving layer, making accurate impurity compensation difficult and leading to low yield in device production.
Innovation Solution
A semiconductor stacked body structure is introduced, featuring a control layer with a decreasing concentration of group V elements between the light-receiving layer and the diffusion blocking layer, reducing the sharp change in conduction band level and minimizing carrier accumulation, thus enhancing device sensitivity without the need for precise impurity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a diffusion blocking layer is disposed between the contact layer and the light-receiving layer to inhibit impurity diffusion, then impurity diffusion is reduced, but carrier accumulation occurs at the interface which compromises device sensitivity
Solution Approach 1:
An undoped InGaAs layer is introduced as an intermediary between the diffusion blocking layer and the light-receiving layer. This intermediary layer prevents direct contact between the two, thereby eliminating the interface where carrier accumulation occurs, while still maintaining the impurity blocking function through the adjacent doped layer.
Solution Approach 2:
The single diffusion blocking layer structure is segmented into multiple functional layers: a doped diffusion blocking layer for impurity inhibition and an undoped InGaAs layer for carrier accumulation prevention. This segmentation allows each layer to perform its specific function independently without interfering with the other.
2Reliability
If impurity compensation is attempted to reduce carrier accumulation, then sensitivity may be improved, but accurate impurity control becomes difficult leading to low production yield
Solution Approach 1:
The function of impurity compensation is extracted from the diffusion blocking layer and transferred to the undoped InGaAs layer. By removing the need for precise impurity control in the compensation layer, the production process becomes simpler and more reliable, directly improving manufacturing yield.
Solution Approach 2:
The impurity concentration parameter in the diffusion blocking layer is changed to a fixed, easily controllable value. The complex parameter control previously needed for impurity compensation is eliminated, replacing it with a simpler structural solution that maintains sensitivity without compromising yield.
3Manufacturing precision
If the conduction band level changes sharply at the interface, then the diffusion blocking function is effective, but carrier accumulation occurs which reduces device sensitivity
Solution Approach 1:
The undoped InGaAs layer serves as a mediator that buffers the sharp conduction band level change. It creates a gradual transition zone that prevents the abrupt interface effect causing carrier accumulation, while still allowing the diffusion blocking layer to maintain its impurity blocking effectiveness.
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 improves the sensitivity of the light-receiving device by reducing carrier accumulation and inhibiting depletion layer extension, facilitating easier production and increased yield.
Implementation Method 1
a diffusion blocking layer containing a III-V group compound semiconductor and a p-type impurity that generates a p-type carrier, the diffusion blocking layer having a p-type impurity concentration of 1×10^16 cm^-3 or less
Data Source
AI summary
A semiconductor stacked body includes a base layer containing a III-V group compound semiconductor, a light-receiving layer containing a III-V group compound semiconductor, a control layer containing a III-V group compound semiconductor and disposed in contact with the light-receiving layer, a diffusion blocking layer containing a III-V group compound semiconductor and a p-type impurity that generates a p-type carrier, the diffusion blocking layer having a p-type impurity concentration of 1×1016 cm−3 or less, and a contact layer containing a III-V group compound semiconductor and having p-type conductivity. These layers are stacked in this order. The concentration of an element in the control layer, the element being identical to a group V element contained in the light-receiving layer, is lower on a main surface of the control layer adjacent to the diffusion blocking layer than on a main surface of the control layer adjacent to the light-receiving layer.