The Semiconductor Institute has made important progress in the research of silicon-based epitaxial quantum dot lasers

Based on the mature and stable CMOS process, the silicon-based optoelectronic integrated chip integrates the huge number of functional devices required by the traditional optical system on the same chip, greatly improving the information transmission and processing capacity of the chip, and can be widely used in large data centers, 5G / 6G, the Internet of things, supercomputers, artificial intelligence and other emerging fields. Due to the low luminous efficiency of silicon (Si) materials, the epitaxy of III-V semiconductor materials such as gallium arsenide (GaAs) with high luminous efficiency on CMOS-compatible Si substrates, and epitaxy and preparation of lasers is recognized as the best on-chip light source scheme. Due to the large lattice mismatch, polarity mismatch and thermal expansion coefficient mismatch between Si and GaAs materials, it is necessary to solve a series of key scientific and technical difficulties to develop high-performance silicon-based epitaxial lasers on CMOS-compatible non-declination Si substrates.

Recently, the Yang Tao-Yang Xiaoguang team of the Key Laboratory of Materials Science of the Institute of Semiconductors has made important research progress in the field of silicon-based epitaxial quantum dot lasers and their doping regulation. The team used molecular beam epitaxy technology to reduce the defect density of silicon-based GaAs material to the order of 106cm-2 at the total thickness of 2700nm buffer layer. The layered InAs/GaAs quantum-dot structure is used as the active region, and the "P-type modulation doping + direct Si doping" domain double doping regulation technology is proposed and applied to the active region for the first time, and the low power on-chip light source which can work at high temperature is developed. At room temperature, the continuous output power of the device exceeds 70mW, and the threshold current is 30% lower than that of the P-doped laser with the same structure. The maximum continuous operating temperature of the device exceeds 115°C, which is the highest value for a CMOS-compatible non-declination silicon based direct epitaxial laser reported in the public. These techniques and results provide the key scheme and the core light source for the realization of high density silicon-based optoelectronic integrated chips with ultra-low power consumption and high temperature stability.

The relevant research results are entitled Significantly enhanced performance of InAs/GaAs quantum dot lasers on Si (001) via spatially separated co-doping is published June 1, 2023 in Optics Express. Two weeks after the article was published, Semiconductor Today, a leading international magazine in the semiconductor industry, reported and recommended the results in a column.

This research was supported by the National Key research and development Plan and the National Natural Science Foundation.

FIG. 1 Structure diagram of silicon epitaxial quantum dot laser and scanning electron microscopic image of the front cavity of the device.

FIG. 2 Continuous output P-I curves of the double-doped regulated device and the reference device at different operating temperatures, illustrated by the spectrum of the double-doped regulated laser at 115℃ and 175mA continuous current.

Source: Institute of Semiconductors, Chinese Academy of Sciences