Study On The Monolithic Optoelectronic Integrated Circuits Based On CMOS Compatible Technology

Optical network has brought some advantages of wide bandwidth, good transparency, wavelength routing characteristics, compatibility and expansibility. However, the performance of electrical signal processing is always excellent, the terminal of the communication network such as computer still uses electrical signals. In the optical communication system, the conversion between electrical signals and optical signals is an indispensable process, which needs some key components such as high-speed optical modulators and high-speed photodetectors. Therefore, in the optical communication system, optoelectronic integrated circuit (OEIC) is the fundamental way to realize high speed optical communication.Silicon is the most widely applied semiconductor materials because of the low cost. The standard silicon CMOS technology has greatly matured in the integrated circuit (IC) industry and the silicon integrated optoelectronic technology is fully compatible with CMOS process. As a result, kinds of silicon photonic devices such as high speed optical modulator, photodetector and laser have been successively developed. Monolithic OEIC receivers integrating the silicon photodetector and silicon CMOS circuits have been reported frequently. In this paper, we propose another type OEIC chip which integrates an optical MZM or an optical Mach-Zehnder Switch and an analog CMOS driving circuit. The chip is fabricated on SOI material using CMOS compatible technology.The characteristic of SOI material, the electric structure of the p-i-n diode, the structure of analog CMOS integrated circuits and the requirements of the CMOS process are considered together to design feasible process flows. By using these process flows, the silicon optical waveguide devices based on free carrier dispersion (FCD) effect and the CMOS drive circuits are designed and the monolithic optoelectronic hybrid integrated circuit chip is successfully fabricated. In China, we are the first group to fabricate this kind of chip by employing a commercial CMOS process. The whole process is carried out, including the design of optical devices and CMOS driving circuit by 0.8μm CMOS technology in Silan Integrated Circuit Ltd., layout design, assistance to the process design of the chip fabrication and the frequent testing of the chip. According to the testing results, the parameters of the chip are improved and applied to the 0.18μm technology. Based on this technology, the optical devices and the CMOS driving circuits are designed once again.The test results of the monolithic OEIC chip in this thesis shows:the extinction ratio (ER) of the MZM is close to 20 dB and the small-signal gain of the CMOS driving circuit is about 26.9 dB. A 50 mV and 10 MHz sine wave signal is amplified by the driving circuit and then drives the MZM successfully. As thus, the feasibility of the monolithic OEIC chip with the optical modulator and the CMOS driving circuit based on CMOS technology is verified.