(molecular nanoelectronics)

Molecular nanoelectronics and the emergence of quantum effects in nanotransistors

Researcher  and author: Dr.   (   Afshin Rashid)


Note: The emergence of quantum effects with the shrinking of transistor dimensions and entering the range below 100 nm, the behavior of individual atoms gradually becomes significant and important.

According to the dimensions of the silicon atom, which is about 1.46 angstroms (0.146 nm) and  taking into account the distance of interatomic bonds, we come to the conclusion that when we are in the dimensions below 100 nm, with only a few tens of silicon atoms We are busy. Decreasing the number of silicon atoms in the transistor causes the problem of crystal defects to become a serious challenge. Because a small crystal defect, either caused by silicon atoms or impurity atoms added to silicon, will cause many changes in the electrical behavior of the transistor and will remove the transistor from its intended use.





By reducing all the horizontal and vertical dimensions of the transistor, the electric charge density in different areas of the nano-transistor  increases, or in other words, the number of electric charges per unit area of ​​the nano-transistor increases. This event has two  negative consequences: First, with the increase in electric charge density, the possibility of electric charge discharge from the insulating areas of the transistor increases   , and this event causes damage to the transistor and its failure. This event is similar to the discharge of  excess electric charge between the cloud and the ground in the phenomenon of lightning, which causes the ionization of air molecules into  negative and positive ions. Secondly  , with the increase of the electric charge density, electrons may  leave the range of the radius of one atom and enter the range of the radius of the adjacent atom under the influence of repulsive or abduction forces whose value has now increased. this The phenomenon is called tunneling in quantum physics. Electron tunneling from one atom to the adjacent atom is a phenomenon that  happens a lot between electrons in small dimensions. This phenomenon is the basis of the work of some electronic components and some  nanoscopes. But in nanotransistor, this phenomenon is not a useful phenomenon, because electron tunneling from one atom to the adjacent atom may  continue and cause an electric current. Although this electric current may be very  small, but because it is unwanted and unanticipated, it acts as a leaky path for electric current  and changes the electrical behavior of the nano-transistor.

Conclusion:

Minimizing transistors and entering dimensions below 100 nanometers in the performance range of nanoelectronics technology, although it  has many advantages, but it faces various challenges. 

Researcher  and author: Dr.   (   Afshin Rashid)

Specialized doctorate in nano-microelectronics