Researches On The Abnormal Response And Latchup Effect Of PV-HgCdTe Linear Array Detector Induced By Light

Infrared detectors have been made rapid development and have been widely used in the industrial,life,scientific research and national defense fields etc,due to its advantages that is to convert infrared wave into the form by which people can use it.HgCdTe detector has become the crucial products in infrared field because of its excellent performances,naturally researches on its characteristics become one of hot issues.Laser irradiation effect research is an important method which helps research materials and device performance.In this paper,with this method,the unusual phenomena and the latchup effect of HgCdTe detector are studied systematicly,its research results have great significance to improve the understanding of the characteristics of HgCdTe material and devices,and to improve the performance of material and devices.The main researches are as follows:1.The experiments found that the output voltage of linear array detector exist the phenomena of supersaturated down-voltage,zero voltage output which is different from the usual signal.after the output voltage of the detector reaches saturation,with the increase of the laser energy,output voltage V2 decreases and V2 and V1 which is the basal signal output voltage fall together to zero volt when V2 is down to the same value as V1.Researches have shown that the open circuit voltage of detection chip raiseses the bias voltage Vb after laser energy is beyond the saturation threshold of detector,which will inducesupersaturated down-voltage and zero voltage output.2.the experiments found that the different damaged units have different voltage outputs without laser irradiation,the damaged units can still response to the light,but the sensitive spectral range of the damaged units shifts to the short-wave direction known as blue shift.For example,the damaged unit is more sensitive to 1064 nm than undamaged units.Researches have shown that the change of depletion layer resistance of damage units induced the different level voltage output of damaged units without laser irradiation,and the increase of composition x of Hg1-xCdxTe materials of damaged units induced the blue shift of the damaged units.3.The latchup effect of linear array HgCdTe is found again in our experiments,but the wavelength and pulsewidth of laser used are different from the previous experiments..The mechanism of latchup effect has been also deeply studied.Researches have shown that there are the internal PNPN SCR structure in the photosensitive element and readout circuit structure,and large current triggers SCR structure and forms latchup effect.In addition,the possible protective measures of latchup effect have been discussed.