METHOD FOR DOPING SEMICONDUCTING SILICON WITH PHOSPHORUS TO CREATE P-N JUNCTIONS Russian patent published in 2017 - IPC H01L21/22 

FIELD: chemistry.

SUBSTANCE: method for doping semiconducting silicon with phosphorus is as follows. Semiconductor is placed into magnetic field. Silicon sheets are further treated with hydrofluoric acid (HF), boiled in ammonium-peroxide solution, washed with deionised water and dried by centrifuging; silicon sheets are placed into a preheated to T₁=950°C diffusion furnace. Diffusion annealing is carried out for thirty minutes (t₁=30 min) under oxygen (O₂) while temperature increasing linearly to T₂=1200°C. Two-stage isothermal annealing for thirty-fifty minutes (t₂=30-50 min), for the first half of the time under the atmosphere of phosphorous pentoxide and nitrogen (P₂O₅+N₂), for the second half - under oxygen (O₂). Following the isothermal annealing the furnace is cooled for thirty minutes down to temperature T₁. Silicon doping process in diffusion furnace requires as follows: oxygen (O₂), fed into the quartz chamber - 45 l/h max, nitrogen - 650 l/h max. The p-n junction depth increased up to 15-19.3 micrometer.

EFFECT: improved chemical purity.

6 cl, 1 tbl, 1 dwg