- SEMI MF1388 - Test Method for Generation Lifetime and Generation Velocity of Silicon Material by Capacitance-Time Measurements of Metal-Oxide-Silicon (MOS) Capacitors
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 February 1, 2018. Available at www.semiviews.org and www.semi.org in July 2018; originally published by ASTM International as ASTM F1388-92; previously published April 2012.
Generation lifetime and generation velocity are strongly influenced by electrically active deep-level impurities and physical imperfections in the silicon, and are thus an indication of the quality of the silicon wafer. Such electrically active deep-level impurities and physical imperfections can cause excessive p-n junction leakage, poor dynamic random access memory (RAM) refresh performance, and ‘dark current’ degradation in computer-controlled display (CCD) memories, delay lines, filters, and imagers.
This Test Method is suitable for monitoring the generation lifetime and generation velocity of silicon wafers in the following situations:
Incoming and Outgoing Inspection of Silicon Wafers — Due to the length of measurement time at room temperature and destructive nature of the test, such inspection should be restricted to a small number of wafers. In the absence of an interlaboratory evaluation of the precision of this Test Method, its use for materials acceptance is not recommended unless the parties to the test mutually agree on the method's repeatability and on the correlation they can obtain.
Contamination Monitoring of Processing Equipment, Materials, or Procedures — Such monitoring requires using silicon wafers of known generation lifetime and generation velocity, obtained from lots sampled by previous MOS capacitance-time characterization, to fabricate the MOS capacitors. The results can then be compared to the known material values to determine the effect of the processing. Due to variations in generation lifetime and generation velocity of typical groups of silicon wafers, a large number of measurements may be required to produce statistically significant results.
Research and Development Purposes — For the evaluation of new materials, processes, and methods involved in the fabrication of semiconductor devices.
This Test Method covers the measurement of generation lifetime and generation velocity of silicon wafers.
Referenced SEMI Standards
SEMI M59 — Terminology for Silicon Technology
SEMI MF1153 — Test Method for Characterization of Metal-Oxide-Silicon (MOS) Structures by Capacitance-Voltage Measurements