composed of two Cu atomic switches with the polymer solid electrolyte (PSE)
sandwiched between two metals (Cu and Ru) as shown in Fig. 13. The switch
turns on or off when a nanometer-scale metallic bridge either appears or disappears
inside a PSE film by biasing voltages. When a positive voltage is applied to a Cu
electrode described in Fig. 13a, the Cu
+ ions are supplied from the Cu electrode to
PSE. The Cu
+ ions are neutralized and precipitated at the Ru electrode. Subsequently, the precipitated Cu forms conducting bridges between the two electrodes,
thus changing the conductance to an ON state. Conversely, by applying a negative
voltage to the Cu electrode, the Cu bridge is ionized and disappears, resulting in an
OFF state. Each state is nonvolatile and the switching between the two states is
repeatable. An LSI using NanoBridge
® is fabricated with high reliability configuration. A series of switch of NanoBridge
® is implemented in lookup tables and cross
bar switches in a FPGA, and high off state impedance is realized. The ON resistance
is small enough for operations [20], and the OFF current is below 10 nA. The
switching is repeatable up to 1000 times and each state is nonvolatile. The physical
formulation is shown in Fig. 14. A programmable FPGA with NanoBridge
® is
shown in Fig. 15a, and the evaluated device with a plastic package is shown in
Fig. 15b. The FPGA does not include a default CPU.
(a)
(b)
Solid electrolyte
Cu
Ru
Cu
Y
X
C
ON
OFF
Fig. 13 Switching behavior of NanoBridge
® [26]
Atomic Switch FPGA: Application for IoT Sensing Systems in Space
51
sandwiched between two metals (Cu and Ru) as shown in Fig. 13. The switch
turns on or off when a nanometer-scale metallic bridge either appears or disappears
inside a PSE film by biasing voltages. When a positive voltage is applied to a Cu
electrode described in Fig. 13a, the Cu
+ ions are supplied from the Cu electrode to
PSE. The Cu
+ ions are neutralized and precipitated at the Ru electrode. Subsequently, the precipitated Cu forms conducting bridges between the two electrodes,
thus changing the conductance to an ON state. Conversely, by applying a negative
voltage to the Cu electrode, the Cu bridge is ionized and disappears, resulting in an
OFF state. Each state is nonvolatile and the switching between the two states is
repeatable. An LSI using NanoBridge
® is fabricated with high reliability configuration. A series of switch of NanoBridge
® is implemented in lookup tables and cross
bar switches in a FPGA, and high off state impedance is realized. The ON resistance
is small enough for operations [20], and the OFF current is below 10 nA. The
switching is repeatable up to 1000 times and each state is nonvolatile. The physical
formulation is shown in Fig. 14. A programmable FPGA with NanoBridge
® is
shown in Fig. 15a, and the evaluated device with a plastic package is shown in
Fig. 15b. The FPGA does not include a default CPU.
(a)
(b)
Solid electrolyte
Cu
Ru
Cu
Y
X
C
ON
OFF
Fig. 13 Switching behavior of NanoBridge
® [26]
Atomic Switch FPGA: Application for IoT Sensing Systems in Space
51