Multi-Layer Semiconductor Device for Enhanced Light Responsivity
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Solution Overview
Problem
Conventional semiconductor devices with PIN diode-type structures have poor response characteristics due to narrow depletion regions and require negative bias for complete depletion, limiting their responsivity to incident light.
Innovation Solution
A semiconductor device configuration with multiple layers, including a first and second semiconductor layer of different conductivity types, a third intrinsic semiconductor layer, and a fourth semiconductor layer with a lower doping concentration, creating a second depletion region for carrier multiplication and enhanced electric field, thereby improving responsivity without the need for negative bias.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PIN diode-type structure is used, then the device can convert light into electric signal, but the depletion region is narrow resulting in poor response characteristics
Solution Approach 1:
The device is divided into multiple semiconductor layers with different conductivity types (first n-type layer, first p-type layer, second n-type layer, second p-type layer) creating multiple depletion regions. This segmentation allows the total depletion width to be distributed across multiple regions, increasing the overall light absorption volume while maintaining the PIN diode functionality for light-to-electric signal conversion.
Solution Approach 2:
The invention transitions from a conventional single-layer PIN diode structure to a multi-layer stacked structure with alternating conductivity types. This dimensional expansion in the vertical direction creates additional depletion regions without increasing the lateral area, effectively increasing the total depletion width available for light absorption and carrier generation.
2Reliability
If high reverse bias voltage is applied to multiply carriers, then response characteristics improve, but negative bias is required which complicates operation
Solution Approach 1:
The invention changes the structural parameters by introducing multiple semiconductor layers with different doping concentrations and conductivity types. This structural modification creates multiple depletion regions that generate stronger internal electric fields, enabling effective carrier multiplication at lower or zero bias conditions, thereby eliminating the requirement for negative bias operation.
Solution Approach 2:
The multi-layer structure with alternating conductivity types generates internal electric fields through its own construction, without requiring external negative bias application. The built-in potential differences across the multiple junctions create the necessary electric fields for carrier multiplication and light detection, making the device self-sufficient in generating the required fields for operation.
3Force
If the doping concentration difference between first and fourth semiconductor layers is greater than 4×10^18 atoms/cm³, then electric field strength increases, but device complexity increases
Solution Approach 1:
The invention applies different doping concentrations to specific local regions (different semiconductor layers) to optimize electric field distribution. The first and fourth semiconductor layers have significantly different doping concentrations (>4×10^18 atoms/cm³ difference) to create strong electric fields in specific depletion regions, while other layers have appropriate doping levels for their specific functions, achieving localized field enhancement without uniformly complicating the entire device structure.
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 semiconductor device achieves higher electric field generation at the same bias voltage, resulting in excellent responsivity to incident light and a wider depletion area, enhancing light detection capabilities.
Implementation Method 1
A light receiving device using a semiconductor converts electromagnetic energy into electric energy based on the photoelectric effect generated in a semiconductor
Implementation Method 2
Carriers may be multiplied by increasing an electric field in a depletion region through application of a high reverse bias voltage to a PIN diode-type light receiving device
Data Source
AI summary
A semiconductor device of an embodiment includes first and second semiconductor layers having different conductivity types; a third semiconductor layer interposed between the first and second semiconductor layers; and a fourth semiconductor layer interposed between the second and third semiconductor layers, having a lower doping concentration than that of the first semiconductor layer and the same conductivity type as the first semiconductor layer, wherein the difference in doping concentration between the first semiconductor layer and the fourth semiconductor layer may be greater than 4×E18 atoms/cm3.