Toward High-Speed VLSI: Semi-Classical Model of Nanoscale MOSFET with SiO₂/Si/SiO₂ Embedded Quantum Well Channel

A coupled nanoscale transistor, with both electronic and photonic properties is designed, modelled, investigated and simulated. In this transistor, called MOSQWELL (MOS Quantum Well), a SiO₂/Si/SiO₂ quantum well structure is embedded between the source and the drain terminals, serving as an ultra-thin channel (1.6 to 2.4 nm) which offers discrete energy levels, thus enabling controlled inter-sub-band transitions (ISBT) in the visible and the short-wave infrared (SWIR) ranges. Analytical and numerical complementary models are developed to test the discrete quantum properties and their impact on the drain current. To test the device functionality, it is necessary to use a correct model of the potential distribution and the electric field in the device, and to check the eigenvalues of the Schrödinger-Poisson equation. The main future advantages of such a component are the free area increase per chip, the elimination of parasitic currents through the use of an insulating buried oxide layer, the potential light emission (controlled using V_GS, V_DS, and t_Si), and the fully VLSI compatible architecture for rapid integration in the industry, using Si and SiO₂ materials only. In a post-Moore's law world where there is a limit in the ability to further reduce transistor size and number per area, MOSQWELL transistors can be the next step for Photonic Integrated Circuits (PICs), significantly increasing the capabilities of optical communication over the existing transistors.