Gigahertz Large-Area-Electronics RF Switch and its Application to Reconfigurable Antennas

Device, Circuit, and System Design for Enabling Giga-Hertz Large-Area Electronics

“…14 shows drainto-source current at breakdown 𝐼𝐼 𝐺𝐺𝐺𝐺,𝐵𝐵𝐵𝐵𝐵𝐵𝑀𝑀𝐵𝐵 , and the breakdown power 𝑃𝑃 𝐵𝐵𝐵𝐵𝐵𝐵𝑀𝑀𝐵𝐵 (𝑃𝑃 𝐵𝐵𝐵𝐵𝐵𝐵𝑀𝑀𝐵𝐵 = 𝐼𝐼 𝐺𝐺𝐺𝐺,𝐵𝐵𝐵𝐵𝐵𝐵𝑀𝑀𝐵𝐵 • 𝑉𝑉 𝐺𝐺𝐺𝐺 ) versus 𝑉𝑉 𝐺𝐺𝐺𝐺 . Regardless of TFT biasing and operation regime (saturation or linear), a roughly constant breakdown power is observed for all 𝑉𝑉 𝐺𝐺𝐺𝐺 values, which suggests thermallyinduced breakdown [15].…”

“…Operation as an active device imposes stricter limits on TFT operation than operation as a passive device [15], [18]. For active-device operation, the TFT is typically biased in the saturation regime to provide current/power amplification.…”

“…The sheet resistance of this composite metal stack measured at DC is ~0.4 Ω/𝑠𝑠𝑠𝑠. A multi-finger layout is employed [15] to divide the total width of the TFT into multiple fingers, thereby reducing the resistance in the direction of the channel width.…”

“…The breakdown mechanism sets the upper limit for biasing voltages and thus the achievable 𝑓𝑓 𝑇𝑇 and 𝑓𝑓 𝑀𝑀𝑀𝑀𝑀𝑀 , when ZnO TFTs are biased in the saturation regime as active devices. This has motivated circuit and system topologies where ZnO TFTs are used as passive devices, biased in the linear regime (i.e., with smaller 𝑉𝑉 𝐺𝐺𝐺𝐺 and 𝐼𝐼 𝐺𝐺𝐺𝐺 , and thus lower power dissipation 𝑉𝑉 𝐺𝐺𝐺𝐺 • 𝐼𝐼 𝐺𝐺𝐺𝐺 ) [15]. Though in this way higher frequencies have been achieved for LAE systems, in the present paper we keep our focus on the important regime of active-device TFT operation for circuits and systems.…”

“…As an example, the actual circuit and system operating frequencies of today's mainstream crystalline-substrate integrated circuit technologies (Si-CMOS and III-V semiconductors) are 10 − 100 × lower than the device-level frequency limits, due to practical losses. In contrast, recent research shows that the achievable operating frequency of LAE-based circuits and systems can be very close to the device-level frequency limits, by appropriately leveraging the high-quality, low-loss passives and substrates enabled by LAE fabrication [15], [16], [18], and by properly aligning circuit topologies with the particular device attributes derived from LAE materials [19].…”