A tunnel FET design for high-current, 120 mV operation

A Multiscale Modeling of Triple-Heterojunction Tunneling FETs

“…However, even for broken-gap GaSb/InAs HJ TFETs, the tunnel probability is low due to quantum confinement induced band gap overlap [5]- [7]. A number of designs have been proposed to further improve the performance of the GaSb/InAs HJ TFETs [5]- [14]. Among these designs, the triple HJ (3HJ) designs [11]- [14] significantly boost the tunnel probability of the HJ TFETs by adding two additional, properly designed, HJs: one in the source and the other in the channel.…”

“…A number of designs have been proposed to further improve the performance of the GaSb/InAs HJ TFETs [5]- [14]. Among these designs, the triple HJ (3HJ) designs [11]- [14] significantly boost the tunnel probability of the HJ TFETs by adding two additional, properly designed, HJs: one in the source and the other in the channel. For n-type 3HJ TFETs [11], atomistic quantum ballistic transport simulations have shown, that extremely high I ON of 800µA/µm (460µA/µm) could be obtained at Lg = 30nm (15nm), V DD = 0.3V, and I OFF = 1nA/µm.…”

“…The 3HJ devices' promising ON/OFF current ratio is likely to be degraded by various scattering phenomena, as implied by the large spatial overlap of conduction-and valence-band local density of states (LDOS) at the OFF state [11]- [14]. The effect of electron-phonon scattering on the 3HJ design performance has been examined by the non-equilibrium Green's function (NEGF) approach in the self-consistent Born approximation (SCBA) [14], considering only the diagonal components of the self-energy.…”

“…The 3HJ devices' promising ON/OFF current ratio is likely to be degraded by various scattering phenomena, as implied by the large spatial overlap of conduction-and valence-band local density of states (LDOS) at the OFF state [11]- [14]. The effect of electron-phonon scattering on the 3HJ design performance has been examined by the non-equilibrium Green's function (NEGF) approach in the self-consistent Born approximation (SCBA) [14], considering only the diagonal components of the self-energy. It is found, that the electron-phonon scattering moderately degrades the transistor's I-V characteristics, but the I ON at a given I OFF and V DD remains much larger than that of a GaSb/InAs HJ TFET, when simulated under equal intensity of phonon scattering [14].…”

“…The effect of electron-phonon scattering on the 3HJ design performance has been examined by the non-equilibrium Green's function (NEGF) approach in the self-consistent Born approximation (SCBA) [14], considering only the diagonal components of the self-energy. It is found, that the electron-phonon scattering moderately degrades the transistor's I-V characteristics, but the I ON at a given I OFF and V DD remains much larger than that of a GaSb/InAs HJ TFET, when simulated under equal intensity of phonon scattering [14]. The strong electronelectron scattering, such as the Auger generation [15], present in the heavily doped source (and drain) lead, however, has not been examined yet.…”