Room temperature negative differential resistance of CdF2∕CaF2 double-barrier resonant tunneling diode structures grown on Si(100) substrates

Abstract

The authors have demonstrated the crystal growth of CaF2∕CdF2∕CaF2 multilayered heterostructures on Si(100) substrates as double-barrier resonant tunneling diode structures by a low-temperature growth technique. Current-voltage characteristics were investigated and the authors observed negative differential resistance (NDR) characteristics at room temperature. The peak-to-valley current ratio was 2–8, and 13 at maximum, and peak current density was 80–90A∕cm2. The quantum-well layer thickness dependence of NDR peak voltages is also discussed on the basis of qualitative analytical model using the Esaki-Tsu formula.

Resistance Switching Memory Characteristics of Si/CaF₂/CdF₂ Quantum-well Structures Grown on Metal(CoSi₂) Layer

“…Due to the large ΔE C , leakage current is expected to be suppressed in low level even at room temperature and moreover, voltage for tunneling transport can be controlled by utilizing multi-quantum-well tunneling scheme such as resonant tunneling or sequential tunneling with appropriate design of quantum-well layer thickness sequences. Up to now, we have demonstrated large ON/OFF current ratio of CdF 2 /CaF 2 RTDs larger than 10 5 at RT [4][5][6], which confirmed advantage of the large ΔE C heterostructure material systems. And moreover, we have proposed and demonstrated novel scheme of resistance switching diode or resistance random access memory (ReRAM) cell using Si/CaF 2 /CdF 2 /CaF 2 /Si quantum-well (QW) structure [7,8].…”

Resistance switching memory characteristics of Si/CaF2/CdF2/CaF2/Si resonant-tunneling quantum-well structures

“…One essential building block for nanoscale solid-state devices is the electric potential sequence for controlling electron transport, which can be implemented using the energy band discontinuity at atomically abrupt heterointerfaces. A CdF 2 /CaF 2 /Si heterostructure is an attractive candidate for applications in Si-based integrated devices, such as resonant-tunneling diodes (RTDs) [1][2][3][4][5][6][7][8] and transistor 9,10) Coulomb blockade devices, because of the large conduction band discontinuity (¦E C ³ 2.9 eV) [11][12][13] at the heterointerface and the small lattice mismatch with silicon owing to the similar cubic crystalline structures. Owing to the large ¦E C and energy band gaps (E g values for CaF 2 and CdF 2 are 12.1 14,15) and 8.0 eV, 16) respectively), the leakage current is expected to be suppressed to a low level even at room temperature (RT).…”

Fabrication and Characterization of CdF₂/CaF₂ Resonant Tunneling Floating Gate Metal-oxide-semiconductor Field Effect Transistor Structures

“…CdF 2 /CaF 2 triple barrier resonant tunneling structures are grown in hole array of 100 nm in diameter with 250 nm-interval formed in 10 nm-thick SiO 2 gate oxide region as shown in Fig.1(b). Limitation of crystal growth region in nano-area holes significantly enhance high-quality epitaxial growth of CdF 2 /CaF 2 heterostructures especially on Si(100) [4,5]. Au/Al is used as gate electrode.…”