METHOD OF MANUFACTURE OF A MULTI-SITE HIGH-SPEED SILICON PIN-PHOTOSENSITIVE ELEMENT Russian patent published in 2018 - IPC H01L31/18 

FIELD: manufacturing technology.

SUBSTANCE: invention relates to the production of silicon pin-photosensitive elements (PSE) sensitive to radiation with a wavelength of 1.06 mcm and can be used in electronic optical equipment in which short pulses of laser radiation (10–40 ns) are required to be recorded. Method of manufacturing a multi-site photosensitive element on silicon substrates with a resistivity of more than 20 kΩ⋅cm includes operations of thermal oxidation, diffusion of phosphorus to form regions n⁺-type conductivity, distillation of phosphorus with simultaneous oxidation to grow a protective film of silicon dioxide, diffusion of phosphorus into the back surface of the substrate for gettering of contaminants, removal of the gettering layer, diffusion of boron into the back surface of the substrate to form a contact layer p⁺-type of conductivity, the chemical etching operation of the silica film to produce an antireflection coating and the operation of creating two-layer ohmic contacts to the photosensitive sites, the guard ring and the back layer p⁺-type conductivity by the method of deposition of a gold film with a sublayer of chromium, the thickness of the chromium film on the back layer being 5–6 nm. According to the invention, an ion implantation of boron into the back surface of the substrate and its prolonged distillation are carried out in order to create a thick contact layer p⁺-type of conductivity, as well as complex gettering, including ionic implantation of argon and diffusion of phosphorus into the back surface of the substrate.

EFFECT: increase in the speed and monochromatic impulse sensitivity at a wavelength of 1,06 mcm, a decrease in the level of dark currents of the PSE, and an increase in the percentage of yields suitable for the first stage of fabrication of the PSE.

1 cl, 1 dwg, 1 tbl