Design Of MOCVD In-situ Monitoring Signal Acquisition System Based On DSP

LED lighting as the most popular green light source attracts people's concern.The main raw materials of LED are solid-state semiconductors,so the development of the MOCVD equipment for semiconductor thin film materials is the current situation.The MOCVD in-situ monitoring system is an important part of the MOCVD equipment.The in-situ monitoring system plays an important role in regulating the growth of epitaxial wafers and the adjustment process,which is far-reaching for the process innovation of film growth.In this paper,the signal acquisition part of the MOCVD in-situ monitoring system,selects the embedded control chip DSP C2000 series as the CPU,samples the in situ monitoring signal by multi-channel synchronous pattern,the collected signal through the digital signal processing by Ethernet communication to the monitoring software of the host computer are analysed by the epitaxy engineer.The design of putting the digital signal processing before the host computer,reduces the stream transmission of original signal data largely,reduces the load of the host computer as well.This paper describes the principle of signal generation and the extraction of the signal from situ monitoring instrument,designs the conditioning circuit of the signal source,performs the amplification and filtering operation on the output signal,and designs the voltage conversion circuit of the synchronous signal of the rotating motor.Then,do a detailed explanation about the peripheral circuit design of The minimum system in DSP,A/D conversion chip AD7656 and Ethernet chip W5300;In the aspect of software design,in the DSP integrated software platform CCS V4.2 using the C language to write the main and function program code of DSP,which includes the control logic design of between DSP and AD7656 and between DSP and W5300,the program code design of based on XINTF DMA without CPU intervention data transmission,time domain synchronization average algorithm,W5300 driver and network data transfer;Finally,uses Delphi XE7 to design the network communication control and function panel of host computer interface.Finally,the function of Ethernet data communication and signal ccquisition are debugged and verified.The results show that the function of each module is working normally,and the acquisition system can collect 6 channels of in-situ monitoring source signals at 250 k Hz rate.The system results show that the design results meet the design requirements and get the approval of the epitaxy engineers...