METHOD FOR MANUFACTURING A PLANAR AVALANCHE PHOTODIOD Russian patent published in 2018 - IPC H01L31/107 

FIELD: physics.

SUBSTANCE: essence of the invention lies in the fact that the method for manufacturing a planar avalanche photodiode comprises sequential epitaxial growth on an n-type InP substrate of the an n-type InP buffer layer, n-type InGaAs absorbing layer, InGaAsP separating layer, n-type InP charge layer and an n-type InP multiplication layer; forming a protective layer on the InP multiplication layer; 1st FLG: preferential etching of the light-absorbing region in the protective layer and InP multiplication layer; including etching the light-absorbing region of the protective layer and the InP multiplication layer by a given depth to provide a given etching profile with a positive slope of the side wall to reduce the curvature of the space charge region (creating the effect of a guard ring) and to prevent early edge breakdown; 2nd FLG: preferential etching of the protective layer in the region of the guard ring to the multiplication layer; diffusion from a solid source into a multiplication layer at a given temperature; formation of a light-reflecting layer on the diffusion layer; 3rd FLG: local etching through the photoresist mask of the light-reflecting layer to form a contact window on the light absorbing region; 4th FLG: formation of a layer of the upper electrode on the diffusion region formed on the light-absorbing region; formation of a lower electrode layer on the back side of the substrate, preferential etching of the recess in the light-absorbing region of the InP multiplication layer is carried out by liquid chemical etching, which due to the selection of the etchant, time of etching and orientation of the mask, relative to the crystallographic direction on the plate, indicated by the base cut, provides reproducible depth and an etching profile in said InP layer; diffusion of Zn₃P₂ is carried out in a quenched and sealed quartz ampoule at a given temperature.

EFFECT: use: for manufacturing photosensitive devices.

1 cl, 23 dwg