Research On Electron Multiplication Avalanche Photodiode

Avalanche photodiode is pupolar among scientific research field because of its avalanche multiplication characteristic,and is widely applied in military and civilian field because of its advantages of small volum e,low dark current and fast response speed etc.Under the guidance of basic concept of avalanche amplification photodiode device and the consideration of electric field intensity,avalanche amplification,dark current and other characteristics,this thesis designs and prepares APD device of SAGCM structure through integrating analogue simulation results and practical epitaxial growth experiment to optimize the thickness and mingling conditions of contact layer,charge layer,absorbed layer,amplification layer and gradient layer.Meanwhile,InP avalanche layer structure is optimized and improved based on SAGCM-APD structure.The thesis also prompts to employ In_0.53Ga_0.47As/In_0.52Al_0.48As superlattice to replace SAGCM-APD InP avalanche layer so as to realize electron avalanche structure,increase bandwidth amplification,and decrease excessive noise.The research works mainly including following contents:?1?The basic design concept of nP/InGaAs avalanche photodetector is deeply researched,and the carrier ionization rate concept is introduced.Then,based on the hole-amplification SAGCM structure under the leading of hole-ionization,collision ionization theory is employed to research the electron-hole ionization rates of different materials.Meanwhile,the advantage of high electron ionization rate of superlattice,the avalanche amplification area of superlattice is designed and the device is designed as the electron-amplification-type avalanche amplification diode under the leading of electron ionization.?2?Based on the traditional avalanche photodetector model of SAGCM structure,the theoretical electron-amplification-type avalanche photodetector model with superlattice avalanche area is established.Given the simulated analysis and optimized design toward the model,MOCVD epitaxial technology is employed to conduct epitaxial growth toward the electron-amplification-type avalanche photodetector structure with superlattice avalanche area.And corrosion test is employed to test the growth conditions of all structural layers of experimental film and to identify that the practical growth structure confirms to the structure of theoretical design.?3?Two kinds of preparation technologies,namely mesa technology and planar technology,are explored.Then the domain of photolithographic mask version is designed and manufactured so as to integrate mesa technology and planar technology to a set of mask version.Based on InP base p-in-n type material structure,the current sheets technological process is optimized that the annealing,metal mask layer preparation and corrosion are optimized.Finally,the electron-amplification-type avalanche avalanche photodiode with superlattice avalanche area is prepared.?4?The device packaging technology of test process is optimized and the current-illumination characteristics test is conducted toward the experimental film gained by current sheets technology.Then,based on the test results,the existing problems of the process are analyzed and solved,and the technological parameters are optimized repeatedly,and finally a set of technological conditions which are more reliable and can be repeated is gained.Comparison of SAGCM-APD and APD with superlattice structure avalanche amplification layer is conducted so as to verify the strengthening effect of superlattice structure on avalanche photodiode properties.