Cutoff frequency characteristics of gate‐controlled hot‐electron transistors by Monte Carlo simulation

Abstract

The high‐speed characteristics and off characteristics of a novel transistor with a hot‐electron launcher and a transit layer of an intrinsic semiconductor whose current is controlled by an insulated gate are evaluated by Monte Carlo simulation. The dependences of the cutoff frequency fT on the gate insulator thickness, collector bias voltage, gate length and transit layer length are clarified. For the optimum structure consisting of InP/InGaAs/W as the emitter/transit layer/collector, Au as the gate and bisbenzocyclobutene (BCB) as the gate insulator and the surrounding material, fT is 1.4 THz at the collector current density of 1.6 MA/cm2. The collector current can be controlled over four orders of magnitude by a gate voltage swing of 0.6 V. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Vertical InGaAs Channel Metal–Insulator–Semiconductor Field Effect Transistor with High Current Density

“…When the current density exceeds 1 MA/cm 2 , 10) a cutoff frequency greater than 1 THz can be expected. 5,11) In the fabricated device, the observed drain current density was about 200 kA/cm 2 when the mesa width was 50 nm. 7) Although in this structure, the location of the gate electrode was controlled by the etchback of benzocyclobutene (BCB), it was difficult to simultaneously control the gate location in the vertical direction and the gate dielectric thickness between the mesa structure and the gate electrode.…”

“…[5][6][7][8][9] The electrons extracted from the source region are expected to transport in the channel without any scattering, because of the undoped channel. We can use an InP/InGaAs heterostructure because the device structure is vertical.…”

Improvement in Gate Insulation in InP Hot Electron Transistors for High Transconductance and High Voltage Gain

“…To realize a device with ballistic transportation, we have previously proposed a device with a heterostructure launcher and an undoped transport region. [1][2][3][4] In the proposed device, hot electrons that are extracted from the emitter by the application of an appropriate gate bias travel only in the intrinsic region, and therefore, ballistic transportation is expected. From a Monte Carlo simulation, the estimated speed of hot electrons in a 70-nm-long transport region has been observed to be greater than 7:5 Â 10 7 cm/s.…”

“…From a Monte Carlo simulation, the estimated speed of hot electrons in a 70-nm-long transport region has been observed to be greater than 7:5 Â 10 7 cm/s. 4) For a current density larger than 1 MA/ cm 2 , 5,6) the cutoff frequency has been estimated to be larger than 1 THz. 4) In the previous research involving the study of hot electron transistors with an insulated gate, 3,7) we clearly observed the modulation of collector current by the gate bias.…”

“…4) For a current density larger than 1 MA/ cm 2 , 5,6) the cutoff frequency has been estimated to be larger than 1 THz. 4) In the previous research involving the study of hot electron transistors with an insulated gate, 3,7) we clearly observed the modulation of collector current by the gate bias. The gate current was smaller than the collector current by eight orders of magnitude, thereby confirming gate insulation.…”