Indirect-Bandgap Semiconductor LED for CMOS-Compatible Optical Interconnects
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Solution Overview
Problem
The incompatibility between III-V semiconductor compounds used for optical signal generation and silicon-based CMOS integrated circuits poses a challenge in achieving high-speed and high-bandwidth communication, leading to inefficiencies in optical interconnection.
Innovation Solution
An indirect-bandgap-semiconductor LED with a p-i-n diode structure is developed, which creates a hot electron-hole plasma upon reverse biasing, facilitating direct recombination and efficient light production, thus overcoming compatibility issues and enhancing communication bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If III-V semiconductor compounds are used for optical signal generation, then light emission efficiency is improved, but compatibility with silicon-based CMOS integrated circuits deteriorates
Solution Approach 1:
The patent uses an indirect-bandgap semiconductor layer as an intermediary between the silicon substrate and the desired optical output. This intermediate layer enables direct recombination of electrons and holes to produce light, while remaining compatible with silicon-based CMOS fabrication processes. The intermediary layer bridges the gap between silicon's electrical processing capabilities and the need for efficient optical signal generation.
Solution Approach 2:
The patent changes the bandgap parameter of the semiconductor material from direct-bandgap (III-V compounds) to indirect-bandgap (silicon-compatible materials). By modifying this fundamental material parameter, the invention achieves compatibility with CMOS technology while maintaining light emission capability through engineered recombination mechanisms.
2Adaptability or versatility
If indirect-bandgap semiconductor is used for light emission, then compatibility with silicon-based CMOS is improved, but radiative recombination rate deteriorates
Solution Approach 1:
The patent creates regions with different doping concentrations (p-type and n-type regions) within the indirect-bandgap semiconductor layer. This local variation in material properties enables the formation of p-n junctions with strong internal electric fields, which accelerate carrier recombination and enhance light emission efficiency in specific localized regions while maintaining overall CMOS compatibility.
Solution Approach 2:
The patent introduces dynamic carrier injection through applied voltage to the p-n junction, creating non-equilibrium conditions that dramatically increase the radiative recombination rate. The dynamic injection of carriers overcomes the inherently slow recombination process of indirect-bandgap materials, enabling high-speed optical signal generation compatible with communication requirements.
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 solution significantly increases the radiative recombination rate, enabling efficient light production and addressing the communication bandwidth bottleneck in rack-to-rack and chip-to-chip interconnections, while being compatible with CMOS technology.
Implementation Method 1
creates a hot electron-hole plasma upon reverse biasing
Implementation Method 2
facilitating direct recombination and efficient light production
Data Source
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AI summary
An indirect-bandgap-semiconductor, light-emitting diode (401). The indirect-bandgap-semiconductor, light-emitting diode (401) includes a plurality of portions including a p-doped portion (412) of an indirect-bandgap semiconductor, an intrinsic portion (414) of the indirect-bandgap semiconductor, and a n-doped portion (416) of the indirect-bandgap semiconductor. The intrinsic portion (414) is disposed between the p-doped portion (412) and the n-doped portion (414) and forms a p-i junction (430) with the p-doped portion (412), and an i-n junction (434) with the n-doped portion (416). The p-i junction (430) and the i-n junction (434) are configured to facilitate formation of at least one hot electron-hole plasma in the intrinsic portion (414) when the indirect-bandgap-semiconductor, light-emitting diode (401) is reverse biased and to facilitate luminescence produced by recombination of a hot electron with a hole.