Carbon-based chips will become the mainstream in the future, and semiconductor materials and electronic device testing are the basis of research

[Future Measurable] Series 1:

Carbon-based chips will become the mainstream in the future, and semiconductor materials and electronic device testing are the basis of research

Carbon-based semiconductor materials are developed on the basis of carbon-based nanomaterials. So-called nanomaterials refer to materials with at least one dimension in the three-dimensional space at the nanoscale (1-100nm), including: zero-dimensional materials – quantum dots, nanopowders, nanoparticles; one-dimensional materials – nanowires or nanotubes; two-dimensional materials – nanofilms, graphene; three-dimensional materials – nano solid materials. According to the composition, nanomaterials can be divided into metal nanomaterials, semiconductor nanomaterials, organic polymer nanomaterials and composite nanomaterials.

Since one dimension of nanomaterials reaches nanometer size, its properties will show different characteristics from those of macroscopic materials. These characteristics include: surface and interface effects - lower melting point and higher specific heat; small size effect - conductors become non-conductive, insulators begin to conduct electricity, and superhard properties; quantum size effect and macroscopic quantum tunneling effect. The physical and chemical properties of nanomaterials include: high strength and toughness; high specific heat and thermal expansion coefficient; abnormal conductivity and diffusivity; high magnetic susceptibility. Based on the above characteristics, nanomaterials have been widely used in many fields.

We are more concerned about semiconductor nanomaterials because they are important raw materials for building carbon-based electronic devices.

The so-called carbon-based electronic devices refer to electronic devices that use carbon nanosemiconductor materials (three-dimensional material diamond, two-dimensional material graphene and one-dimensional material carbon nanotubes) as channels - diamond is mainly used for ultra-wide bandgap semiconductor devices; carbon nanotubes can be used to make carbon nanotube field emitters, carbon nanotube CNFETs, single-electron transistors, carbon nanotube sensors, carbon nanotube memories, carbon nanotube switches, etc.; graphene can be used to make zero-bandgap, top-gate graphene field-effect transistors, double-layer graphene transistors, bipolar superconducting graphene transistors, graphene nanoribbon field-effect transistors, etc.

Carbon-based electronic chips are integrated circuits built with CNTs. The reason why carbon-based chips are made of semiconductor carbon nanotubes is that scientists have selected the best solution after testing various semiconductor nanomaterials. Carbon-based chips are considered to be the new dawn of the post-Moore era, mainly because the limit size of carbon nanotubes is roughly the same as that of current silicon-based materials, and the manufacturing process has not changed much. In addition, carbon-based chips have better performance, lower power consumption and higher operating frequency than silicon-based chips (electron mobility 100,000 cm2/VS vs 1,000 cm2/VS, frequency 100 GHz vs 10 GHz).

my country is a world leader in carbon-based chip research, and the research group of Academician Peng Lianmou of Peking University has always been at the forefront of the field of carbon-based chips. Although carbon-based chips are still significantly behind traditional silicon-based chips (14,000 transistors vs billion-level integration), Academician Peng believes that carbon chip technology is expected to become the mainstream chip technology in 15 years, and my country will achieve a curve overtaking in the chip field.

Carbon-based semiconductor materials and electronic device testing

The purpose of testing carbon-based semiconductor nanomaterials is to screen materials and improve their molecular structures, especially for carbon-based chips. When preparing carbon nanotubes, slight differences in curling diameter and angle will affect the conductivity of the carbon nanotubes, which means that it is possible to obtain finished products with metallic properties. Obtaining uniform carbon nanotubes with semiconductor properties is the primary condition for carbon-based chip research.

For one-dimensional materials, IV characteristic tests are mainly used. Since nanomaterials are extremely small in size, the test current they can withstand is extremely small (up to the fA level), the test voltage is extremely low (up to the nV level), and the tested material is easily burned due to self-heating caused by the test. Therefore, it is necessary to select a test instrument with pulse characteristics that is compatible with the performance of the nanomaterial being tested.

For two-dimensional materials and graphene, resistivity, carrier concentration, and carrier mobility testing are important test items, which require the use of four-probe and Van der Pauw methods.

For carbon-based electronic devices and carbon-based chips, the IV characteristics are mainly tested. By changing the number, position and device structure of carbon nanotubes, tests and comparisons are carried out to select the best solution.

Carbon-based semiconductor materials and electronic device testing solutions

There are many types of carbon-based semiconductor materials and electronic devices, and their electrical properties vary. It is necessary to select the best matching SMU for testing. The 4200 semiconductor parameter tester can cover all applications. The specific test plan is as follows.