Rib Waveguide Semiconductor Modulator Carrier Distribution
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Solution Overview
Problem
Current semiconductor devices with optical modulators using silicon photonics technology face limitations in performance enhancement, particularly in the efficiency and miniaturization of optical modulators due to challenges in depletion layer expansion and carrier density control.
Innovation Solution
The semiconductor device incorporates a phase modulation part with a p-type semiconductor region at the central part of the rib waveguide and an n-type semiconductor region surrounding it, allowing for increased depletion volume and efficient carrier density modulation by applying reverse bias, along with a secondary section for voltage application to improve modulation efficiency and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional optical modulator structure is used, then the device can be manufactured with standard processes, but the modulation efficiency is insufficient and the device dimensions are large
Solution Approach 1:
The patent applies local quality by creating a pn junction specifically at the center of the rib waveguide where the optical mode is concentrated. The p-type semiconductor region is formed at the central portion of the rib waveguide, while n-type semiconductor regions are formed on both sides, creating a localized carrier density modulation zone that efficiently interacts with the optical mode without requiring the entire device to be enlarged
Solution Approach 2:
The patent transitions from planar modulation to three-dimensional carrier distribution by forming the p-type region at the center and n-type regions on sides at different lateral positions. This spatial arrangement in multiple dimensions creates an expanded depletion volume that enhances modulation efficiency while maintaining compact device footprint
2Productivity
If the depletion layer is expanded to improve modulation efficiency, then more carriers are available for modulation, but the device length increases
Solution Approach 1:
By concentrating the pn junction structure at the central region of the rib waveguide where the optical intensity is highest, the patent achieves maximum modulation efficiency per unit length. The localized carrier modulation at the mode maximum allows efficient phase modulation without extending the device length
Solution Approach 2:
The patent expands the depletion volume in the lateral dimension by forming n-type regions on both sides of the central p-type region, creating a three-dimensional carrier distribution. This volumetric approach increases the total number of carriers available for modulation without increasing the longitudinal length of the phase modulation part
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 configuration enhances the modulation efficiency of the optical modulator, enables efficient phase change of light, and reduces the device's dimensions while facilitating high-speed operation without increasing the length of the phase modulation part.
Implementation Method 1
an optical modulator OT1... by applying reverse bias, along with a secondary section for voltage application to improve modulation efficiency
Implementation Method 2
an optical waveguide formed of a semiconductor layer formed over a base material via an insulation layer as the transmission line for an optical signal
Data Source
AI summary
The performances of a semiconductor device are improved. The semiconductor device includes an insulation layer, an optical waveguide part formed over the insulation layer, and including a p type semiconductor region and an n type semiconductor region formed therein, and an interlayer insulation film formed over the insulation layer in such a manner as to cover the optical waveguide part. At the first portion of the optical waveguide part, in a cross sectional view perpendicular to the direction of extension of the optical waveguide part, the n type semiconductor region is arranged at the central part of the optical waveguide part, and the p type semiconductor region is arranged in such a manner as to surround the entire circumference of the n type semiconductor region.