Design Of Wideband Noise Acquisition And Analysis System Based On Virtual Instrument And Its Application

Many kinds of electrical noise exist in semiconductor devices, presented at awideband frequency range. These noise signals are generally considered to random intime domain, but may contain rich information about the material property ofseimiconductor devices. Research on low frequency noise shows that low frequencynoise of semiconductor devices indicates the defects and damage in the material,especially1/f noise, thus can be used to evaluate the realiblity of devices. On the otherhand, high frequency part of the noise signal, such as shot noise, is found to be relatedto the structure information and electron transport properties of nano scale devices,thus can be used to enhance manufacturing technology of nano scale devices. Analysisof the noise signal and its application are based on the measurement of noise and aconvenient tool to handle the calculations. Existing low frequency noise analysismethod could only cover the lower range of the whole noise spectrum. Thus a unifiedmethod that can cover the whole range of the spectrum, which means that both lowfrequency and high frequency noise can be measured and analyzed, is needed. In thispaper, a system was designed and set up to provide such a unified method. Thehardware of the system is set up by using a high speed data acquisition cardmanufactured by national instruments and a low noise wideband pre amplifier. Thesoftware is built under the NI labview developing environment. Major work done inthis paper includes:1. The idea of using virtual instruments as a wideband noise measurement andanalysis platform was brought up, based on which the whole system was designedincluding the hardware setup and the software functionality flow and their intergration.2. Based on results above, the data acquisition card and low noise wideband preamplifier was chosen and set up as the hardware of the system. Then the software isbuilt under NI labview environment, which includes following functionalities:highspeed continous data acquisition, power spectrum transformation, data storage, basicnoise analysis, advanced noise spectrum analysis.3. Based on results above, the measurement accuracy and analysis functionalitiesof the system was validated and verified. Then the system was applied to two cases todemonstrate the use of wideband noise analysis in semiconductor devices: one is lowfrequency noise and its application in devices screening and the other is shot noiseanalysis of APD.