METHOD FOR PRODUCING HIGH-SPEED MULTICOMPONENT PHOTODETECTORS BUILT AROUND EPITAXIAL STRUCTURES InGaAs/InP Russian patent published in 2008 - IPC H01L31/18 

FIELD: laser location systems, laser radiation detection, infrared spectrometry, multiple-spectrum fiber-optic communication lines, new-generation night viewing systems.

SUBSTANCE: photodetector producing method includes coating of n-InP/n-In_0.53 Ga₀₄₇ As/n⁺-InP epitaxial wafer incorporating epitaxial layers n-InP/n-In_0.53 Ga_0.47 As and substrate n⁺-InP with silicon nitride film both on n-InP epitaxial layer end and on n⁺-InP one. Diffusion windows are covered with photolithographic layer by way of plasmochemical etching in silicon nitride film on end of n-InP/n-In_0.53 Ga_0.47 As epitaxial layers and marks are formed for further alignment of photomask patterns on n⁺-InP substrate end. Local p-n junction is formed in n-InP/n-In_0.53 Ga_0.47 As epitaxial layers by cadmium diffusion in soldered exhaust ampoule from Cd₃P₂ source. Epitaxial wafer n-InP/n-In_0.53 Ga₀₄₇ As/n⁺-InP is coated with second layer of Si₃N₄ film on end of n-InP/n-In_0.53 Ga_0.47 As epitaxial layers. Contact windows are opened in second layer of Si₃N₄ film and Au/Ti ohmic contacts are made for p⁺ regions. Contact windows are opened in Si₃N₄ film on n⁺-InP substrate side for n⁺-InP region by way of photolithography and plasmochemical etching. Si₃N₄ film remains above p-n junction region in this case that functions as clearing coating. Titanium-sublayer gold is evaporated in vacuum so that metal plating is formed for n⁺-InP substrate contacts. Pattern that affords ohmic contact for n⁺-InP substrate on one end and forms diaphragm limiting shading region by spatial charge region of multicomponent photodetector only on other end is etched in titanium-sublayer gold by photolithographic method.

EFFECT: enhanced speed of photosensitive component due to eliminating non-depleted n-region shading when using planar technology for multicomponent photodetector manufacture.

1 cl, 5 dwg