We demonstrate a hybrid plasmonic−pyroelectric device operating as an uncooled midwavelength infrared detector with narrowband spectral selectivity. The device consists of a plasmonic perfect absorber with a built-in pyroelectric ZnO layer: It consists of a ZnO layer sandwiched by a Au microhole array as a top electrode and a Pt bottom electrode as a template for the uniaxially grown ZnO film. The geometrical design of the plasmonic Au (hole array)/ZnO/Pt system is determined by the numerical electromagnetic simulation and then fabricated by colloidal-mask lithography combined with reactive-ion etching. The fabricated detectors exhibit excellent spectral selectivity at the predesigned plasmonic resonances, which are tunable by changing the Au hole diameters. The results obtained here open up a route for realizing a new type of uncooled spectroscopic infrared detectors with a compact design and simple fabrication process.

Ferroelectricity and crystallinity of TiN/ZrO2/Hf xZr1− xO2 (Hf:Zr = 0.43:0.57; HZO)/SiO2/Si metal–ferroelectric–semiconductor (MFS) capacitors with a top ZrO2 nucleation layer fabricated by low-temperature processes at 300 °C of atomic layer deposition and post-metallization annealing (PMA) were systematically investigated. The HZO (10 nm)-based MFS capacitors without (w/o) and with 2- and 10-nm-thick ZrO2 films (ZrO2-2 nm and ZrO2-10 nm, respectively) were found to form an extremely thin SiO2 interfacial layer (SiO2-IL) with a thickness of one or two monolayers. The HZO film in the TiN/ZrO2/HZO/SiO2/Si capacitors formed the ferroelectric orthorhombic phase even with a low thermal budget of 300 °C; in contrast, that of the w/o capacitor exhibited a predominantly amorphous structure. This result is attributed to the polycrystalline ZrO2 film acting as a nucleation layer for the crystallization of an amorphous HZO film during PMA treatment. Therefore, the remnant polarization (2 Pr) increased in the order of w/o (2.2 µC/cm2) < ZrO2-2 nm (6.8 µC/cm2) < ZrO2-10 nm (15 µC/cm2). The endurance properties of the ZrO2-10 nm capacitor were free from the wake-up effect and exhibited less degradation because of the insertion of a thick ZrO2 film of 10 nm at the TiN/HZO interface, which promoted the preferential formation of the ferroelectric orthorhombic phase and prevented the formation of oxygen vacancies at the ZrO2/HZO interface. These results suggest that superior ferroelectricity with wake-up-free properties and higher fatigue resistance of HZO-based MFS capacitors can be achieved by a low-temperature fabrication technique (300 °C) using a top ZrO2 nucleation layer.

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We studied characteristic of Metal-Insulator-Metal capacitors with ZrO2/high-k/ZrO2 (Z/high-k/Z)-nanolaminate dielectric layers and TiN electrodes. Amorphous Al2O3, (Ta/Nb)Ox (TN) and (Ta/Nb)Ox-Al2O3 (TNA) as high-k interlayer were prepared by atomic layer deposition and post-deposition annealing. The dielectric constant (k) of ZrO2 thin film exhibited about 28 because of tetragonal, orthorhombic and cubic phases. The k value of Z/high-k/Z-nanolaminate dielectric layer is high in order of ZTNZ > ZTNAZ > ZAZ due to the dependence of each k value of Al2O3 (~ 9) and TN (~29). The ZTNAZ layer exhibited lowest leakage current density of 10-8 ~ 10-7 A/cm2 at 0.6 V compared to those of ZAZ and ZTNZ in CET ~ 1.1 nm. We found that the leakage current property of Z/high-k/Z layer is influenced by not only amorphous structure but also band gap width (conduction band offset of ZrO2) of high-k interlayer. We conclude that the TNA material is one of the candidate material as high-k interlayer for future DRAM.