Structural Design And Process Research Of Optical Waveguide Photodetector

With the rapid development of mobile Internet and communication technologies,5G technology has become the focus of the industry in recent years.As an important support for 5G(fifth generation),optical communication technology is also increasingly improving the performance requirements of optical communication chips.As an important component chip of the receiving end of the optical communication network,the photodetector determines the performance of the entire optical communication network system.Especially in the systems of optoelectronic integration(OEIC)and photonic integration(PIC),new requirements are placed on traditional discrete photodetector chips,such as high speed,low power consumption,easy integration with other devices in the system,etc..This paper introduces the structural design and process research of high-speed optical waveguide photodetector.It uses the combination of inputcoupled grating,distributed DBR and face HR coating to solve the problem of large horizontal coupling difficulty and low coupling efficiency of traditional optical waveguide detectors,and solve the problem that the conventional surface incident type photodetectors have contradictory responsiveness and frequency bandwidth,which reduces the test cost of the chip and improves the test efficiency.Research on the key process of fabricating the semiconductor optical waveguide for the structure,and design a complete and effective chip process.The main contents of this paper include the following aspects:1.Study the performance indicators of photodetectors and analyze the performance parameters affecting the technical indicators of photodetectors.Ensuring the performance of optical waveguide detectors that meet the 40 GHz bandwidth requirements.2.The active area of the optical waveguide detector is designed using a PIN structure.The energy band structure,lattice matching and refractive index of the semiconductor materials used were calculated.The dark current,junction capacitance and 3dB bandwidth of the PIN structure were simulated using Silvaco and Matlab software.The PIN structure parameters that meet the 40 GHz bandwidth requirements are ensured.3.According to the theory of optical waveguide,combined with Rsoft software to design the structure of the optical waveguide and the structural parameters of the coupled grating,and the epitaxial structure of the device.The absorption wavelength of the waveguide detector is calculated and the parameters such as the length of the waveguide and the junction capacitance are ensured according to the performance requirements of the device.The principle and structure of distributed Bragg reflector and optical highreflection film were studied.DBR with reflectivity of more than 95% and optical highreflection film of chip end surface with reflectivity of over 99% were designed,which can effectively improve the coupling efficiency of the chip.4.Starting from the semiconductor process technology,some key processes required for the design of the optical waveguide detector are studied.Research and development of the holographic interference exposure process to produce coupled grating,the theoretical study of ICP dry etching and optical dielectric coating process required for device fabrication.The fabrication process and lithography layout of the optical waveguide detector are designed.