Infrared Sensor Semiconductor Stack for Adhesion and Stress Control
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Solution Overview
Problem
The manufacturing yield of semiconductor elements used in infrared sensors, particularly those with a group III-V semiconductor photoelectric conversion layer, is low due to issues with adhesion and stress-related defects in the layers.
Innovation Solution
The semiconductor element design includes a passivation film with non-reducing properties on the second electrode, an electrically-conductive film formed using aluminum, and a light-blocking film with a black resist to reduce stress and improve adhesion, thereby enhancing manufacturing yield and preventing dark-time characteristic deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional insulating layer is provided on the second electrode, then the structure is simple, but adhesion between the second electrode and insulating layer is poor
Solution Approach 1:
The patent applies composite materials by introducing an intermediate layer composed of aluminum oxide and aluminum hydroxide between the second electrode and the insulating layer. This intermediate layer serves as an adhesion promoter that chemically bonds to both the electrode and the insulating layer, creating a composite structure that significantly improves interfacial adhesion and prevents peeling defects.
2Reliability
If the electrically-conductive film thickness is increased, then electrical conductivity is improved, but stress-related defects increase
Solution Approach 1:
The patent optimizes the thickness parameter of the electrically-conductive film to a specific range (5 nm to 50 nm) and controls the aluminum content concentration. By changing these parameters, the film achieves sufficient electrical conductivity while minimizing internal stress that causes peeling and cracking defects during subsequent manufacturing processes.
Solution Approach 2:
The electrically-conductive film is designed as a composite structure containing aluminum particles dispersed in a resin matrix. This composite material configuration allows the film to achieve good electrical conductivity through the aluminum network while the resin component provides mechanical flexibility and stress relief, preventing peeling and cracking defects.
3Productivity
If manufacturing processes are simplified, then productivity is improved, but adhesion problems persist
Solution Approach 1:
The patent incorporates adhesion promotion functionality directly into the intermediate layer formation step, which is performed preliminarily before applying the insulating layer. The intermediate layer is formed by treating the second electrode surface with aluminum oxide and aluminum hydroxide, creating a pre-prepared surface that ensures strong adhesion without requiring additional adhesion promotion steps later in the process.
4Manufacturing precision
If the electrically-conductive film is made thinner, then stress-related defects are reduced, but electrical conductivity deteriorates
Solution Approach 1:
The electrically-conductive film uses a composite material system where aluminum particles or nanowires form a conductive network within a resin matrix. This composite structure enables the film to maintain adequate electrical conductivity even at reduced thicknesses (5-50 nm), because the conductive pathways are formed by the aluminum component while the thin overall structure minimizes internal stress and prevents peeling and cracking defects.
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 improved design enhances adhesion between layers, reduces stress-related defects, and increases manufacturing yield while maintaining dark-time characteristics, leading to more reliable and efficient semiconductor elements for infrared sensors.
Implementation Method 1
the insulating layer having a non-reducing property is provided on the second electrode having a light-transmitting property. This improves adhesion between the second electrode and the insulating layer
Implementation Method 2
a photoelectric conversion layer that includes a group III-V semiconductor such as, for example, InGaAs (indium gallium arsenide). Such a photoelectric conversion layer generates electrical charges through absorption of infrared light (performs photoelectric conversion)
Data Source
AI summary
A first semiconductor element according to one embodiment of the present disclosure includes an element substrate including an element region, a peripheral region, a readout circuit substrate, a first electrode, a second electrode, and an insulating layer. A wiring layer and a first semiconductor layer including a compound semiconductor material are provided as a stack in the element region. The peripheral region is outside the element region. The readout circuit substrate is opposed to the first semiconductor layer with the wiring layer interposed therebetween, and is electrically coupled to the first semiconductor layer with the wiring layer interposed therebetween. The first electrode is provided in the wiring layer and is electrically coupled to the first semiconductor layer. The second electrode is opposed to the first electrode with the first semiconductor layer interposed therebetween. The insulating layer is provided on the second electrode and has a non-reducing property.