Journal ArticleDOI
Single step lithography for double-recessed gate pseudomorphic high electron mobility transistors
TLDR
In this paper, an asymmetric double-recessed gate process achieved through a single lithography step and a combination of wet and dry etching techniques is presented, where a four-layer resist of polymethylmethacrylate (PMMA) and P(MMA-MAA) exposed by electron beam lithography is used.Abstract:
An asymmetric double-recessed gate process achieved through a single lithography step and a combination of wet and dry etching techniques is presented. The double-recessed gate process is beneficial in the fabrication of InGaAs/AlGaAs/GaAs pseudomorphic high electron mobility transistors (PHEMTs) because breakdown voltage is enhanced while surface effects on the drain side of the gate are minimized. In contrast to conventional processes that require two lithography steps, the current process requires only a single lithography step for the asymmetric placement of a T-gate in a wide recess trench. The process utilizes a four-layer resist of polymethylmethacrylate (PMMA) and P(MMA-MAA) exposed by electron beam lithography. Upon development of the resist, a wet selective etch (citric acid:H2O2) is used to define the wide recess trench and then a dry selective etch (SiCl4/SiF4) is used to recess a narrow trench (within the wide recess trench) in which the gate foot rests. This technique can achieve gate length...read more
Citations
More filters
Journal ArticleDOI
Direct three-dimensional patterning using nanoimprint lithography
TL;DR: In this paper, a method based on electron beam lithography and reactive ion etching was developed to fabricate NIL molds with three-dimensional protrusions, including T-gates and air-bridge structures, in a single step imprint in polymer and metal by lift-off.
Patent
Patterning methods for stretchable structures
Kanti Jain,Kevin Lin +1 more
TL;DR: In this paper, processing techniques for fabrication of stretchable and/or flexible electronic devices using laser ablation patterning methods are described. But these techniques are not suitable for large-scale fabrication.
Journal ArticleDOI
Lithography of high spatial density biosensor structures with sub-100 nm spacing by MeV proton beam writing with minimal proximity effect
Harry J. Whitlow,May Ling Ng,Vaida Auzelyte,Ivan Maximov,Lars Montelius,Jeroen A. van Kan,Andrew A. Bettiol,Frank Watt +7 more
TL;DR: In this article, a focused megaelectronvolt (MeV) proton beam writing of poly-(methyl methacrylate) positive resist combined with metal lift-off was used to achieve a few nanometres gap.
Journal ArticleDOI
Efficient removers for poly(methylmethacrylate)
TL;DR: In this article, the authors systematically characterized the effectiveness of several different strippers and found that 1,2-dichloroethane is an efficient PMMA remover, and can produce almost the same surface roughness as the original SiO2 surface (i.e., no contamination).
Patent
High throughput, low cost dual-mode patterning method for large area substrates
TL;DR: In this paper, a high-throughput, low-cost, patterning platform that is an alternative to conventional photolithography and direct laser ablation patterning techniques is presented.