SEMI M88 - Practice for Sample Preparation Methods for Measuring Minority Carrier Diffusion Length in Silicon Wafers by Surface Photovoltage Methods
This Standard was technically approved by the Silicon Wafer Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on August 17, 2018. Available at www.semiviews.org and www.semi.org in January 2019.
Shrinkage and advanced integration of semiconductor components demand lower metal contamination levels in component-fabrication processes and in base silicon wafer substrates. The industry has for some time widely employed surface photovoltage (SPV) measurements of minority carrier diffusion lengths as a technique to assess metal impurities in silicon wafers. Samples, however, often require surface preparation prior to SPV measurements because SPV measurements are sensitive to surface conditions. An associated problem is changes in surface characteristics of samples over time after preparation, samples need to be kept in a standardized condition until their surfaces stabilize. Together these factors created the need for standardization of a preparation method for stable surface with optimized stabilization times.
This Standard provides guidance on sample preparation methods when measuring the minority carrier diffusion lengths of silicon wafers using SPV methods.
This Standard applies to samples with p-type or n-type single-crystal silicon wafers and a polished front surface.
Additionally, it is also applied to silicon wafer which has an oxide layer grown with high-temperature oxidation or chemical-vapor deposition (CVD) films on the front surface of samples.
Referenced SEMI Standards
SEMI C1 — Guide for the Analysis of Liquid Chemicals
SEMI C28 — Specification and Guide for Hydrofluoric Acid
SEMI C30 — Specification and Guide for Hydrogen Peroxide
SEMI M59 — Terminology for Silicon Technology
SEMI MF391 — Test Method for Minority Carrier Diffusion Length in Extrinsic Semiconductors by Measurement of Steady-State Surface Photovoltage