Fabrication of sub-100nm IDT SAW devices on insulating, semiconducting and conductive substrates

Abstract

Keywords: E-beam lithography Insulating layers Charge accumulation Anti-static layerThis work describes the electron-beam (e-beam) lithography process developed to manufacture nano interdigital transducers (IDTs) to be used in high frequency (GHz) surface acoustic wave (SAW) applications. The combination of electron-beam (e-beam) lithography and lift-off process is shown to be effective in fabricating well-defined IDT finger patterns with a line width below 100 nm with a good yield. Working with insulating piezoelectric substrates brings about e-beam deflection. It is also shown how a very thin organic anti-static layer works well in avoiding this charge accumulation during e-beam lithography on the resist layer. However, the use of this anti-static layer is not required with the insulating piezoelectric layer laying on a semiconducting substrate such as highly doped silicon. The effect of the e-beam dose on a number of different layers (of insulating, insulating on semiconducting, semiconducting, and conductive natures) is provided. Among other advantages, the use of reduced e-beam doses increases the manufacturing time.The principal aim of this work is to explain the interrelation among e-beam dose, substrate nature and IDT structure. An extensive study of the e-beam lithography of long IDT-fingers is provided, in a wide variety of electrode widths, electrode numbers and electrode pitches. It is worthy to highlight that this work shows the influence of the e-beam dose on five substrates of different conductive nature.

k-space optical microscopy of nanoparticle arrays: Opportunities and artifacts

“…For the bare glass substrates, an extra step is added: a thin layer of the conducting polymer Espacer 300Z is spin-coated on top of the resist before e-beam lithography in order to avoid charging. 56,57 This conducting layer is removed using deionized water before the development of the resist. All nanostructure dimensions are confirmed using scanning electron microscopy and atomic force microscopy measurements.…”

Plasmonic Enhancement by a Continuous Gold Underlayer: Application to SERS Sensing

“…deposited by spin-coating before the e-beam lithography step in order to avoid charge effects [30,31]. Then, before the development step, this conductive thin layer is removed by deionized water during 1 min.…”

Giant Reflection Coefficient on Sc0.26Al0.74N Polycrystalline Diamond Surface Acoustic Wave Resonators

“…Because of the insulating behavior of the Sc 0.26 Al 0.74 N thin film, as well as of the underlying polycrystalline diamond layer, an organic antistatic layer (Espacer 300Z, Showa Denko) was spun on top of the ZEP520 resist to avoid charge accumulation during e‐beam lithography …”

“…For this, diamond outstands, since it exhibits the highest acoustic velocity. Several studies have reported SAW devices fabricated on heterostructures with diamond substrates working in the 2–15 GHz frequency range …”