New SEMI Standard “SEMI M95” Mercury-Free Era of Epitaxial Layer Evaluation Technology
By Akiko Yoshida, SEMI Japan
Introduction
As the semiconductor industry continues to advance, the global standardization of material evaluation technologies is becoming increasingly vital. SEMI M95, Test Method for Net Carrier Density and Resistivity of Silicon Epitaxial Layer by Capacitance-Voltage Measurements with an Evaporated Metal Schottky Diode, a newly published SEMI Standard developed by the Japan Chapter of the global Silicon Wafer Technical Committee in collaboration with the Japan Society of Newer Metals (JSNM), addresses this need. In semiconductor device design, precise control of net carrier density and resistivity in silicon epitaxial layers is essential for ensuring device performance. SEMI M95 enables safer and more sustainable measurement of these critical parameters, setting a new benchmark for the industry.
Background: Transition from Mercury Probe and JSNM’s Role
Traditionally, carrier density and resistivity measurements of silicon epitaxial layers relied on the capacitance-voltage (CV) method using mercury probes (SEMI MF1392). However, environmental regulations such as the Minamata Convention have restricted mercury use, creating an urgent need for safer, sustainable alternatives.
Japan Society of Newer Metals (JSNM) played a pivotal role in addressing this challenge by developing and standardizing the evaporated metal Schottky diode CV measurement method as JSNM-SI-003. SEMI M95 builds upon this foundation, reorganizing it into an international SEMI Standard format. This collaboration ensures that proven Japanese technology now serves as a global benchmark.
Measurement Method | Key Features | Environmental Impact | Standardization Status |
Mercury Probe (SEMI MF1392) | Short Turn- Around Time (TAT) for process control | Mercury usage poses environmental risk | International SEMI Standard |
Evaporated Metal Schottky Method (SEMI M95 / JSNM-SI-003) | Mercury-free, improved safety, High accuracy | Low | JSNM Standard →International SEMI Standard |
Table 1: Comparison of Measurement Methods
Technical Overview of SEMI M95
SEMI M95 specifies a test method for measuring net carrier density and resistivity in silicon epitaxial layers using capacitance-voltage (C-V) measurements with an evaporated metal Schottky diode. The method covers n-type and p-type wafers across a wide range of carrier densities and resistivities. It replaces mercury-based techniques with a mercury-free approach, improving safety and sustainability. The procedure involves fabricating high-purity metal Schottky electrodes on epitaxial wafers, performing C-V measurements, and calculating carrier density and resistivity profiles. The method is destructive and primarily used for process control, material evaluation, and device development.
International Collaboration and Future Outlook
The development of SEMI M95 exemplifies strong collaboration between JSNM and SEMI. Future initiatives would include standardizing non-contact measurement methods originated from Europe and expanding international cooperation to meet diverse industry needs.
Message to the Industry
SEMI M95 combines environmental responsibility with reliable measurement technology. Companies already using the evaporated metal Schottky method can comply with the new standard without additional investment. This collaboration between JSNM and SEMI strengthens quality assurance and traceability across the semiconductor supply chain. We invite stakeholders to participate in ongoing SEMI Standards activities and contribute to future advancements.
Get Involved
SEMI Standards development activities take place throughout the year in all major manufacturing regions. To get involved, join the SEMI International Standards Program at: www.semi.org/standardsmembership.
For more information, please visit our main Web site and current events page. If you have any questions regarding SEMI Standards activities, please contact your local SEMI Standards staff.
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SEMI
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December 8, 2025