BS ISO 21820:2021

This standard BS ISO 21820:2021 Fine ceramics (advanced ceramics, advanced technical ceramics). Ultraviolet photoluminescence image test method for analysing polytypes of boron- and nitrogen-doped SiC crystals is classified in these ICS categories:

• 81.060.30 Advanced ceramics

This document specifies a test method for determining the polytypes and their ratios in silicon carbide (SiC) wafers or bulk crystals using ultraviolet photoluminescence (UVPL) imaging. The range of SiC is limited to semiconductor SiC doped with nitrogen and boron to have a deep acceptor level and a shallow donor level, respectively. The SiC wafers or bulk crystals discussed in this document typically show electrical resistivities ranging from 10^?3 ohm · cm to 10^?2 ohm · cm, applicable to power electronic devices.

This method is applicable to the SiC-crystal 4H, 6H and 15R polytypes that contain boron and nitrogen as acceptor and donor, respectively, at concentrations that produce donor-acceptor pairs (DAPs) to generate UVPL. In 4H-SiC the boron and nitrogen concentrations typically range from 10¹⁶ cm^?3 to 10¹⁸ cm^?3. Semi-insulating SiC is not of concern because it usually contains minimal boron and nitrogen; therefore deep level cannot be achieved.