Diamond scribe tools in III-V semiconductor materials research
Optoelectronic, high-frequency and high-power electronic devices are often based on non-silicon semiconductors. The main technology for preparing such device structures is the chemical vapour deposition from organometallic compounds (OMCVD), where the semiconductor multilayer structures are deposited from the vapour phase onto the monocrystalline semiconductor or ceramic wafer (substrates).
The basic materials research produces unique wafers with semiconductor layer stacks which has to be operatively divided into the pieces for further characterization with various measuring methods. The process has to be operative; the characterization results of the previous sample determine the conditions for the next deposition experiment.
It is quite usual that in one OMCVD research laboratory many types of substrates are processed. Nitride semiconductors can be deposited on sapphire, silicon, silicon carbide or gallium nitride substrates and arsenide’s and phosphides on gallium arsenide, indium phosphide or gallium phosphide substrates. Because the wafers will undergo the further characterization their particle or chemical contamination or heating during the sample preparation is not acceptable. From this reason scribing with conventional tools (e.g. glass scribers, scalpels etc.), sawing or laser cutting is not applicable.
In 2009 we found Tecdia as the producer of the professional scribing tools for semiconductor industry (advertisement in one of the magazines like III-V`s Review, Solid State Technology, Semiconductor Today). In that time their tools were designed for the use in the professional scribing machines. Such equipment is too expensive for the university or government research laboratory. In addition, the sample dimensions and orientation towards the main crystallographic planes depend on the characterization method. This is why we preferred cutting the wafers into the samples by hand.
After a short communication with Tecdia they agreed to use the scribing tools by hand using a simple tool holder. We ordered 10 pc of 4 types.
Example of sapphire two inch wafer divided into samples for characterization in scanning electron microscope (SEM), atomic force microscope (AFM), high resolution X-ray diffractometer and by optical (PL) and Hall effect (Hall) measurements.
Experiences: when the scribing tool is used by the experienced user its lifetime is more than one year. Very important is to use quality optical microscope for checking the scriber cutting point state and cleanliness before its utilization. Than the operator has to be particular in holding the tool in the proper orientation and angle against the divided crystal.
Using the scribing tool by hand is not trivial and not everybody has enough patience to use it in the right way. The newcomers use it very often as a pencil, what leads to the damage of the cutting edges and the precise scribing tool changes into an ordinary nail.
Now, when Tecdia offers scribing tools as a part of the easy-to-use scribing system called the “Handy Wafer Scriber” we are expecting that the process of dividing our wafers will be more comfortable, superior and less time consuming.
Dr. Stanislav Hasenöhrl