M09300 - SEMI M93 - Test Method for Quantifying Basal Plane Dislocation Density in 4H-SiC by X-Ray Diffraction Topography/Imaging

 Basal plane dislocations (BPDs) are detrimental for devices manufactured on 4H-SiC substrates, especially for bipolar devices for power electronics. Most BPDs are transformed into threading edge dislocations (TEDs) when growing epitaxial layers on top of 4H-SiC substrates, but a small fraction is also transferred into the epitaxial layer or may result in the formation of stacking faults (SFs), both being critical defects potentially causing device failure. The density and distribution of BPDs are therefore important parameters describing the quality of a substrate. The specification of these parameters helps to select the appropriate material for a certain task. The quantification of BPDs is possible by X-ray diffraction topography (XRT)—also known as X-ray diffraction imaging (XRDI). This Test Method provides information on the procedure to measure the BPD density using this technique and can be used for acceptance testing.This Test Method covers the determination of BPD density on round test slices and commercial 4H-SiC substrates using XRT/XRDI. The BPD density is used as a measure of the crystallographic perfection of a crystal. This Test Method describes the requirements of the sample quality, the procedure to obtain a topogram suitable for BPD density measurement and to calibrate the results against results from etch pit data. Referenced SEMI Standards (purchase separately)SEMI M55 — Specification for Polished Monocrystalline Silicon Carbide WafersSEMI M59 — Terminology for Silicon TechnologySEMI M81 — Guide to Defects Found in Monocrystalline Silicon Carbide SubstratesSEMI M83 — Test Method for Determination of Dislocation Etch Pit Density in Monocrystals of III-V Compound Semiconductors Revision HistorySEMI M93-0624 (technical revision)SEMI M93-0923 (first published)