In this paper we discuss some physical limits for scaling of transistors and conducting paths inside of semiconductor integrated circuits (ICs). Since 40 years only a semiconductor technology, mostly the CMOS and the TTL technologies, are used for fabrication of integrated circuits on an industrial scale. Miniaturization of electronic devices in integrated circuits has technological limits and physical limits as well. In 2010 best parameters of commercial ICs shown the Intel Core i5-670 processor manufactured in the technology of 32 nm. Its clock frequency in turbo mode is 3.73 GHz. A forecast of the development of the semiconductor industry (ITRS 2011) predicts that sizes of electronic devices in ICs circuits will be smaller than 10 nm in the next 10 years. At least 5 physical effects should be taken into account if we discuss limits of scaling of integrated circuits.

The electron field and photo-field emission from GaN nanostructures has been analyzed in this review. In order to explain the obtained experimental results, a model was proposed taking into account the change in carrier concentration distribution in the main and the satellite valley during the emission process. The lowering of work function (due to the increased number of carriers in the satellite valley) can explain the decrease in the Fowler-Nordheim plot slope. It was shown that the energy difference between the main and satellite valley in GaN was decreased in the case of quantum confinement, thus increasing the probability of electron transition from Γ to X valley at same electric fields.

Investigations of electron photo-field emission demonstrated that the Fowler–Nordheim plots of the emission current have different slopes for nonilluminated and illuminated devices. A model based on the electron emission from valleys having different specific electron affinities is proposed to explain the experimental results. In the absence of illumination the emission takes place only from the lower valley. Upon UV illumination and presence of a high electric field at the emitter tip, the upper valley of the conduction band appears to be occupied by electrons generated at the valence band.