Group for deposition of silicon nanostructures
The patent concerns the possibility of obtaining growth processes at low temperatures (<250 ° C) compatible with a substrate consisting of a CMOS (complementary metal-oxide semiconductor) integrated circuit, therefore with the possibility of industrial applications. The high surface-to-volume ratio and small size of silicon nanowires makes them attractive candidates for fabricating a large variety of ultra-sensitive sensors.
The patent proposes to heat the nanometer droplets which are the catalyst of the deposition process, leaving the substrate at a permissible temperature, for example 200 °C. The heating of sole droplets can occur through microwave irradiation, for example from 1.5GH commercial generators. At these frequencies the surface conduction is activated in the metals, in particular the terminal wall, consisting of the susceptible and the support plane, reflects the field the electromagnetic field. The substrate on which the deposition occurs is to be supported by a dielectric support, so as to expose the sample to a high electromagnetic field. The nanometric droplet layer is spaced from that terminal conductive plane, so that the tangential electrical field is not null. Under the action of the tangential electric field, metal droplets absorb EM (electromagnetic field) energy by heating.
- Biological sensors, even with dimensions much smaller than those of cells, capable of detecting the external potentials of the cell itself;
- Efficient chemical sensors;
- Single nanowire solar cells, which offer greater light capture and reduce manufacturing costs.
- Possibility of deposition on CMOS circuits as substrates;
- Possibility of depositing nanometric structures on the surface of CMOS integrated circuits, which allows you to create a wide range of sensors directly coupled with the reading and control electronics.