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Browse Prior Art Database

Preparation of Arsenic Source for Sealed Tube Diffusions

IP.com Disclosure Number: IPCOM000094106D
Original Publication Date: 1966-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Benjamin, CE: AUTHOR [+3]

Abstract

Arsenic-silicon powder is used as a diffusant source for a highly controllable sealed tube diffusion into silicon wafers. This powder is made by placing silicon powder and a mass of solid arsenic in a sealed tube. A uniform vapor pressure source of arsenic is obtained since arsenic sublimes at 372 C degrees at 1 mm of mercury. The pressure of arsenic in the tube is controlled by the mass of arsenic initially placed in the tube. The ratio of the masses of the silicon powder and arsenic, and the time and the temperature of the batch determine the resulting composition of the arsenic-silicon powder diffusion source. The source composition is important since it determines the arsenic surface concentration in the subsequent sealed tube diffusion into silicon wafers.

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Preparation of Arsenic Source for Sealed Tube Diffusions

Arsenic-silicon powder is used as a diffusant source for a highly controllable sealed tube diffusion into silicon wafers. This powder is made by placing silicon powder and a mass of solid arsenic in a sealed tube. A uniform vapor pressure source of arsenic is obtained since arsenic sublimes at 372 C degrees at 1 mm of mercury. The pressure of arsenic in the tube is controlled by the mass of arsenic initially placed in the tube. The ratio of the masses of the silicon powder and arsenic, and the time and the temperature of the batch determine the resulting composition of the arsenic-silicon powder diffusion source. The source composition is important since it determines the arsenic surface concentration in the subsequent sealed tube diffusion into silicon wafers. An arsenic-silicon powder diffusion source is made by placing a mass of pure arsenic in a tube containing pure silicon powder, sealing the tube and heating the tube at about 1105 degrees C for 24 hours.

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