We report on the fabrication and characterization of quantum-doped graded-like channel heterojunction field-effect transistors (HFETs) by molecular beam epitaxy (MBE) using a multiple pulse doping technique. The extended equations describing the piecewise doping profiles have been developed to derive the transconductance and second-harmonic to fundamental ratio. It is found that the thickness of depletion width dominates the maximum transconductance and the high doping gradient offers the device linearity. Two HFETs with different doping gradients have been fabricated to elucidate this concept. We obtain the maximum extrinsic transconductance of 165 mS mm −1 . Both have broad plateaus on their transconductance versus gate-to-source voltage profiles. Further, the devices exhibit a gate-to-drain and a drain-to-source breakdown voltage larger than 25 V. The very small output conductance and good pinch-off characteristics indicate good confinement of the electrons in a quantum-doped channel.
This paper reports on the fabrication and characterization of graded pulse-doped channel AlGaAs/InGaAs/ GaAs heterojunction field-effect transistors (HFET's). Triple pulse-doped sheets, δ(n 1)=1.2×1012, δ(n 2)=4×1011, δ(n 3)=1×1011 cm-2 from buffer to gate is used as an active channel. Typical drain-to-source and gate-to-drain breakdown voltages are larger than 25 V. The further enhancement in breakdown voltage is using the following methodology: 1) a strained AlGaAs insulator, 2) an InGaAs quantum-well like channel, and 3) less impurity scattering in the graded pulse-doped channel. The maximum transconductance is 160 mS/mm with an available current density of 250 mA/mm. Further increasing the δ(n 1) to 4×1012 cm-2, the maximum transconductance is 165 mS/mm. The available current density is increased to 480 mA/mm. Moreover, their transconductance vs. gate voltage profiles display broad plateaus. The fabricated devices exhibit a small output conductance of 0.3 mS/mm. The evaluated open-drain voltage gain is as high as 500. These results have better performances than those of i-AlGaAs/n+-InGaAs HFET's fabricated by our system.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.