Solution‐processed high‐k oxide dielectric via deep ultraviolet and rapid thermal annealing for high‐performance MoS₂ FETs

Abstract

So far most of MoS2‐based devices have been demonstrated on oxide gate dielectrics (e.g., SiO2, Al2O3, HfO2, etc) deposited by vacuum process or on polymer gate dielectrics. In this study, we report electrical characteristics of multilayer MoS2 transistors fabricated on solution‐processed high‐k AlOx gate dielectric via deep ultraviolet (DUV) activation in combination with rapid thermal annealing process at 250 °C. The solution‐processed AlOx sol–gel film exhibited low leakage current of about 1.49 μA cm−2 at 1 MV cm−1 and a relative dielectric constant (k) of ∼6.1 at 1 kHz. The fabricated MoS2‐FETs exhibit median field‐effect mobility of ∼23.3 cm2 V−1s−1, threshold voltage of ∼ 0.79 V, subthreshold slope of ∼0.30 V dec−1, and on/off current ratio of ∼107. The electrical performance can be further improved by optimizing the AlOx sol–gel film as well as the device structure, and the result implies that the solution‐processed high‐k AlOx is promising for TMDC–based device applications.

Electronically Tunable Transparent Conductive Thin Films for Scalable Integration of 2D Materials with Passive 2D–3D Interfaces

“…However, following this nucleation period, deposition of a nanometer‐thin conformal AlO x coating on the as‐deposited amorphous carbon layer was achieved. While charge carriers can directly tunnel through the nanometer‐thin AlO x coating (Figure S6b, Supporting Information), we determined a breakdown electric field of ≈5.7 MV cm –1 for a 5.5 nm thick alumina layer (Figure S6c, Supporting Information), which is consistent with literature [ 38 ] and demonstrates the applicability of the nc‐C/AlO x structure for field‐effect transistors.…”

High-kGate Dielectrics for Emerging Flexible and Stretchable Electronics

“…The DUV photochemical activation of sol–gel films revealed that an intense photon flux can deliver sufficient energy to the precursor film to decompose the organic species and form a dense M–O–M phase, similar to that achieved via high-temperature annealing (Figure a) . More recently, the DUV method was extended to various MO dielectrics including Al 2 O 3 and Zr-doped Al 2 O 3 (ZAO). ,,− These dielectric films were fabricated by spin-coating aluminum nitrate nonahydrate/2-methoxyethanol and zirconium­(IV) acetyl-acetonate/2-methoxyethanol as Al and Zr sources, respectively, and the DUV process decomposed the precursors within 5 min at 253.7 nm via a radical-mediated mechanism . Both the film capacitance and leakage current increase as the Zr:Al molar ratio increases, with the optimal ZAO films (∼35 nm thick) having a Zr:Al molar ratio of 5:95.…”

Templated dewetting: designing entirely self-organized platforms for photocatalysis

“…118 Nevertheless, this configuration provides also direct light irradiation of the TiO 2 /M/environment interface, and charge carriers formed in its close proximity can thus be effectively transferred to reactants. 119 – 122 …”