Impact of Source to Drain Tunneling on the Ballistic Performance of Si, Ge, GaSb, and GeSn Nanowire p-MOSFETs

Abstract

We investigated the effect of material choice and orientation in limiting source to drain tunneling (SDT) in nanowire (NW) p-MOSFETs. Si, Ge, GaSb, and Ge 0.96 Sn 0.04 nanowire MOSFETs (NWFETs) were simulated using rigorous ballistic quantum transport simulations. To properly account for the non-parabolicity and anisotropy of the valence band the k·p method was used. For each material, a set of six different transport/confinement directions were simulated to identify the direction with the highest ON-current (I ON ). For Ge, GaSb, and GeSn [001]/110/110 oriented NWFETs showed the best ON-state performance, compared to other orientations. Our simulation results show that, despite having a higher percentage of SDT in OFF-state than silicon, GaSb [001]/110/110 NWFET can outperform Si NWFETs. We further examined the role of doping in limiting SDT and demonstrated that the ON-state performance of Ge and GeSn NWFETs could be improved by reducing the doping in the source/drain (S/D) extension regions. Finally, we analyzed the impact of increased injection velocity in [001]/110/110 oriented GaSb and GeSn NWFETs, as a result of the application of uniaxial compressive stress, and showed that when compared at a fixed OFF-current (I OFF ) with unstrained NWFETs, uniaxial compressive stress deteriorates the ON-state performance due to an increase in OFF-state SDT current component.

Quantum transport simulation of the two-dimensional GaSb transistors

“…The effective masses of ML GaSb and h-GaSb range from 0.070m 0 to 0.685m 0 . The electron effective masses except for BL GaSb's, under 0.10m 0 , are much less than bulk Si (0.273m 0 to 0.367m 0 ) [28] . It is noted that the values of the electron and hole effective mass of the BL GaSb are closed.…”

Recent advances in single crystal narrow band-gap semiconductor nanomembranes and their flexible optoelectronic device applications: Ge, GeSn, InGaAs, and 2D materials

“…Semiconductor NWs, a one-dimensional nanostructure with a diameter of a few nanometers and a length in the micrometer scale, are the fundamental building block of both electronic 8 and photonic devices. 9–11 However, the quality of NWs depends crucially on substrates and growth methods.…”

“…NWs and NMs both showed great promise in a wide range of applications for flexible electronic devices, especially in the wearable and healthcare areas. 6,7 Semiconductor NWs, a one-dimensional nanostructure with a diameter of a few nanometers and a length in the micrometer scale, are the fundamental building block of both electronic 8 and photonic devices. [9][10][11] However, the quality of NWs depends crucially on substrates and growth methods.…”

Accuracy of equivalent model in band-to-band tunneling simulation of semiconductor nanowires

“…The EM-based method has been applied to various cases. [16][17][18][19][20][21][22][23][24] In EM, a narrower target window reduces the basis size and thus the computational load. However, on the other hand, if the target window is made too narrow, the accuracy of the calculation suffers.…”