GB/T 42263-2022Determination of nitrogen content in silicon single crystal—Secondary ion mass spectrometry method (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules for Standardization Documents" drafting.

1 Scope

This document describes a secondary ion mass spectrometric method for the determination of nitrogen content in silicon single crystals.

This document is applicable to the determination of nitrogen content in silicon single crystal with doping concentration of boron, antimony, arsenic and phosphorus less than 1 x 10^20cm-3 (0.2%). The range is not less than 1 x 10^14cm-3.

Note: The nitrogen content in silicon single crystal is calculated by the number of atoms per cubic centimeter.

2 Normative references

The contents of the following documents constitute the essential provisions of this document through normative references in the text. Among them, dated references For documents, only the version corresponding to the date is applicable to this document; for undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 14264 Terminology of semiconductor materials

GB/T 22461 Surface Chemical Analysis Vocabulary

GB/T 32267 Analytical instrument performance measurement terms

3 Terms and Definitions

The terms and definitions defined in GB/T 14264, GB/T 22461 and GB/T 32267 apply to this document.

4 Principles

Under the condition of high vacuum (vacuum degree better than 5 x 10^-7Pa), the primary ions generated by the cesium ion source, after being accelerated, purified and focused, are bombarded A variety of particles are sputtered out by hitting the surface of the silicon single crystal sample. The ions (that is, secondary ions) are drawn out, and the ions with different mass-to-charge ratios are separated by a mass spectrometer.

Separate the ions, record the nitrogen-silicon compound ion (14N28Si-) and the main element silicon (28Si- or 29Si- or 30Si-) in the sample under different rate conditions ionic strength. The relative sensitivity factor method is used to quantitatively analyze and calculate the content of nitrogen in the silicon single crystal and the background nitrogen content of the instrument.

5 Interfering factors

5.1 Nitrogen in the silicon oxide on the sample surface may affect the accuracy of the nitrogen content test results.

5.2 Nitrogen adsorbed to sample surfaces from secondary ion mass spectrometer (SIMS) instrument sample chambers and fixtures may affect nitrogen content test results. the accuracy of the result.

5.3 When testing nitrogen, 14N28Si ions with a mass number of 42 are used. Carbon will interfere with the test of nitrogen content in the form of 12C30Si, thus affecting Accuracy of Nitrogen Test Results.

5.4 The vacuum degree of the sample chamber will affect the accuracy of the nitrogen content test results.

5.5 The sample analysis surface within the window of the sample holder should be flat to ensure that when each sample moves to the analysis position, its surface and ion collection The inclination of the optical system should not change, otherwise the accuracy of the test results will be reduced.

5.6 The accuracy of the test decreases significantly with the increase of the sample surface roughness.