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Abstract A negative‐capacitance high electron mobility transistor (NC‐HEMT) with low hysteresis in the subthreshold region is demonstrated in the wide bandgap AlGaN/GaN material system using sputtered BaTiO3as a “weak” ferroelectric gate in conjunction with a conventional SiNxdielectric. An enhancement in the capacitance for BaTiO3/SiNxgate stacks is observed in comparison to control structures with SiNxgate dielectrics directly indicating the negative capacitance contribution of the ferroelectric BaTiO3layer. A significant reduction in the minimum subthreshold slope for the NC‐HEMTs is obtained in contrast to standard metal‐insulator‐semiconductor HEMTs with SiNxgate dielectrics—97.1 mV dec−1versus 145.6 mV dec−1—with almost no hysteresis in theID–VGtransfer curves. These results are promising for the integration of ferroelectric perovskite oxides with III‐Nitride devices toward NC‐field‐effect transistor switches with reduced power consumption.
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Investigation of the Determining Factors for the “Mobility Boost” in High‐ k ‐Gated Transparent Oxide Semiconductor Thin‐Film Transistors
Abstract In metal‐oxide thin‐film transistors (TFTs), high‐kgate dielectrics often yield a higher electron mobility than SiO2. However, investigations regarding the mechanism of this high‐k“mobility boost” are relatively scarce. To explore this phenomenon, solution‐processed In2O3TFTs are fabricated using eight different gate dielectrics (SiO2, Al2O3, ZrO2, HfO2, and bilayer SiO2/high‐kstructures). With these structures, the total gate capacitance can be varied independently from the semiconductor–dielectric interface to study this mobility enhancement. It is shown that the mobility enhancement is a combination of the effects of areal gate capacitance and interface quality for disordered oxide semiconductor devices. The ZrO2‐gated TFTs achieve the highest mobility by inducing more accumulation charge with higher gate capacitance. Surprisingly, however, when the gate capacitance is held constant, no mobility enhancement is observed with the high‐kgate dielectrics compared to SiO2.
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- PAR ID:
- 10360019
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Electronic Materials
- Volume:
- 7
- Issue:
- 5
- ISSN:
- 2199-160X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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