Semiconductor Junction With Moss-Burstein Zone for Dark Current Reduction
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Solution Overview
Problem
Semiconductor structures used for detecting infrared electromagnetic radiation have high dark current at room temperature due to thermal agitation, leading to reduced sensitivity and spatial resolution, and require complex passivation processes to minimize crosstalk between structures.
Innovation Solution
A semiconductor structure with a third zone exhibiting a Moss-Burstein effect is introduced, surrounding the junction to limit lateral current and reduce thermal electron-hole pair generation, while a confinement layer and polarization means are used to manage dark current and crosstalk without requiring etching and passivation of flanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If semiconductor structures are used for detecting infrared electromagnetic radiation at room temperature, then detection capability is provided, but dark current increases due to thermal agitation
Solution Approach 1:
The patent modifies the electrical parameters of the semiconductor structure by introducing a highly doped third zone that changes the Fermi level position and creates a modified depletion region. This parameter change suppresses thermal generation of electron-hole pairs at room temperature, thereby reducing dark current while maintaining detection capability
Solution Approach 2:
The patent introduces a third zone with specific high doping concentration localized around the junction periphery. This local modification creates a specific electrical field distribution and depletion region geometry that targets and suppresses lateral carrier diffusion and thermal generation only in the critical peripheral areas, without affecting the overall detection function
2Ease of manufacture
If conventional junction structures are used, then semiconductor fabrication is simplified, but crosstalk occurs between adjacent structures due to high minority carrier diffusion length
Solution Approach 1:
The third zone is positioned specifically at the periphery of the junction to create a localized electrical field that confines minority carriers. This local modification prevents carrier diffusion into adjacent structures, eliminating crosstalk and improving spatial resolution without requiring complex fabrication processes
Solution Approach 2:
The highly doped third zone acts as an intermediary region between the depletion region and the bulk semiconductor. It creates a modified depletion region that extends laterally, serving as a barrier that prevents direct interaction between adjacent junctions through carrier diffusion
3Object-generated harmful factors
If mesa structures are used to eliminate lateral current, then dark current from periphery is reduced, but passivation operations become complex and expensive
Solution Approach 1:
The patent replaces the mechanical/physical approach of mesa etching and passivation with an electrical field-based solution. The highly doped third zone creates an electrical field configuration that naturally suppresses lateral carrier flow, eliminating the need for complex passivation operations while achieving the same dark current reduction goal
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 structure achieves low dark current and reduced crosstalk at room temperature, enhancing sensitivity and spatial resolution without the need for complex passivation processes, and allows for efficient detection of infrared radiation.
Implementation Method 1
said third zone exhibiting a concentration of majority carriers sufficient to exhibit an increase in the apparent gap due to a Moss-Burstein effect
Implementation Method 2
when a photon, having an energy greater than that of the forbidden band of the semiconductor material, penetrates the semiconductor junction, that- this will generate an electron-hole pair and therefore a current in the junction
Implementation Method 3
a dark current, that is to say a junction current in the absence of any electromagnetic radiation, of high value, this current originating from the generation of electron-hole pairs linked to the thermal agitation, this in particular due to the Auger recombination phenomenon
Data Source
Figure 1~2b
Figure 3~4
Figure 5
AI summary
The invention relates to a semiconductor structure (100, 100a, 100b) able to receive electromagnetic radiation and convert it into an electrical signal, such a structure (100, 100a, 100b) comprising a semiconductor substrate (150) having a first surface (151) defining a longitudinal plane, and a first zone (110, 110a, 110b) of a first conductivity type housed in the substrate (150) with a second zone (120, 120a, 120b) of a second, opposite conductivity type, in order to form a semiconductor junction. A means for limiting lateral current is provided and comprises a third zone (130) housed in the substrate and making lateral contact with the second zone (120, 120a, 120b), said third zone (130) being of the second conductivity type, the majority carriers of which are electrons. The third zone (130) has a sufficiently high majority carrier concentration to increase the bandgap via the Moss-Burstein effect.