This work demonstrates the benefit of a lower contact barrier height, and hence reduced contact resistivity (ρc), using a low work-function metal (Yb) in unpinned metal-interfacial layer-semiconductor (MIS) contacts on n-type Ge. Fermi-level unpinning in MIS contacts on n-Ge is first established by introducing a 2 nm TiO2−x interfacial layer between various contact metals (Yb, Ti, Ni, Pt) and n-Ge. Further, Yb/TiO2−x/n-Ge MIS contact diodes exhibit higher current densities (up to 100×) and lower effective contact barrier height (up to 30%) versus Ti/TiO2−x control devices over a wide range of TiO2−x thickness (1–5 nm). Finally, low work-function Yb combined with doped TiO2−x having a low conduction band offset with Ge and high substrate doping (n+-Ge: 2.5×1019 cm−3) is shown to result in an ultra-low ρc value of 1.4 × 10−8 Ω cm2, 10 × lower than Ti/TiO2−x control devices.

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Remotely empowered wireless sensor networks use different energy resources including photovoltaic solar cells, wireless power transmission, and batteries. As another option the electromagnetic energy available in the ambient can be harvested to power these remote sensors. This is particularly valuable if it is desirable to harvest the ambient energy available in the wide range of electromagnetic spectrum. This has motivated the research for developing energy harvesting devices which can absorb this energy and produce a DC voltage. Rectenna, an antenna coupled with a rectifier, is the main component used for absorbing electromagnetic radiation at GHz and THz frequencies. Rectifying MIM tunnel diodes are able to operate at tens and hundreds of GHz frequency. As the preliminary steps towards development of high-frequency rectifiers, this paper presents fabrication and DC characterization of two new MIM diodes, Ti-TiO 2 -Al and Ti-TiO 2 -Pt. G-V analysis of the fabricated diodes verifies tunneling. Brinkman-Dynes-Rowell model is used to extract oxide thickness of which the derived value is around 9 nm. Ti-TiO 2 -Pt diode exhibits rectification ratio of 15 at 0.495 V, which is more than rectification ratio reported in earlier works.

We study how nitridation, applied to SiON gate layers, impacts the reliability of planar metal-oxide-semiconductor field effect transistors (MOSFETs) subjected to negative and positive bias temperature instability (N/PBTI) as well as hard breakdown (HBD) characteristics of these devices. Experimental data demonstrate that p-channel transistors with SiON layers characterized by a higher nitrogen concentration have poorer NBTI reliability compared to their counterparts with a lower nitrogen content, while PBTI in n-channel devices is negligibly weak in all samples independently of the nitrogen concentration. The Weibull distribution of HBD fields extracted from experimental data in devices with a higher N density are shifted towards lower values with respect to that measured in MOSFETs, and SiON films have a lower nitrogen concentration. Based on these findings, we conclude that a higher nitrogen concentration results in the aggravation of BTI robustness and HBD characteristics.

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