Study On The Mesa Etching Of Extended Wavelength Detector Of In Ga As

The short wavelength infrared In Ga As detector has the advantages of working at room temperature and high detectivity. It has been widely used in space observation, environmental monitoring and military field. Based on the application requirements of short wavelength infrared In Ga As detector, this paper mainly research on the mesa etching process of In Ga As detector and etching damage, in order to improve the performance of extended wavelength In Ga As focal plane detector.By means of orthogonal experimental design method to study the roles of low physical etching Cl2/N2 ICP etching processing parameters, and analysis of etching rate and surface morphology, the suitable process condition is: temperature 170 ℃, Cl2: N2 = 10:30 sccm, ICP power 500 W, RF power 160 W, the pressure 6m T. The optimized process parameters and old process parameters were verified. From the I-V curves of the devices, as well as the relationship between the dark current density and temperature etc., it was found that the device of optimized parameters of dark current is not obvious improvement, the preliminary analysis is that the selection of parameters does not take into account the etching damage, such as DC bias, which result in electrical performance is not ideal, the further study is needed.Orthogonal experimental design method is used to research the technology parameters of Cl2/CH4/H2 etching extended wavelength In Ga As detector, respectively using atomic force microscope(AFM) and scanning electron microscope(SEM) measure the etching bench height and morphology. The roughness of samples and selective etching ratio are obtained. After a set of tetragonal experiments, the SEM and AFM images are also analyzed, optimization of process conditions has been obtained: 60℃, ICP power 1800 W, RF power 75 W, pressure 4 m T. Under this condition the DC bias is 132 V, roughness is small, and mesa verticality is perfect.Introducing the new method of conductive AFM(C-AFM) characterization to analysis the material surface defects of extended wavelength detector, test the i-v curve of the micro area, and research on the relationship between material surface micro-area leakage current and the device electrical characteristics, the main components of the dark current density is analyzed, which verify the C-AFM results. It provide effective basis for optimization of process conditions of experimental analysis and promoting the performance of the In Ga As detector.