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Determining the Dopant Concentration in Subcollectors

IP.com Disclosure Number: IPCOM000082305D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Hoffmeister, WW: AUTHOR [+2]

Abstract

The actual, and not only the electrically active, concentration of dopants, such as arsenic, present after subcollector diffusion can be determined by the X-ray fluorescence method.

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Determining the Dopant Concentration in Subcollectors

The actual, and not only the electrically active, concentration of dopants, such as arsenic, present after subcollector diffusion can be determined by the X- ray fluorescence method.

Because of the shallow depth of the subcollector diffusion, the X-ray fluorescence radiation even of those doping atoms penetrated deepest is excited. The X-ray fluorescence radiation is not noticeably absorbed by the semiconductor material. Therefore, the X-ray fluorescence emerging from the semiconductor material is strictly proportional to the dopant concentration.

If the same area of test wafers doped over their full surface are irradiated by the X-rays, the accurate concentration of the dopant can be calculated from the magnitude of the characteristic X-ray fluorescence radiation diffracted by the analyzer crystal and striking the counter, using calibration data obtained by the absolute method of neutron activation analysis.

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