Vacuum-Free Self-Powered Parallel Electron Lithography with Sub-35-nm Resolution

The critical dimension, throughput, and cost of nanoliihography are central to developing commercially viable high-performance nanodevices. Available top-down lithography approaches to fabricate large-area nanostructures at low cost, such as controllable nanowire (NW) array fabrication for solar cells applications, are challenging due to the requirement of both high lithography resolution and high throughput. Here, a minimum 35 nm resolution is experimentally demonstrated by using a new mask fabrication technique in our demonstrated vacuum-free high-throughput self-powered parallel electron lithography (SPEL) system, which uses large-area planar radioactive beta-electron thin film emitters to parallel expose e-beam resist through a stencil mask. SPEL is the first-time demonstrated vacuum-free electron lithography, which overcomes the membrane mask distortion challenge that was shown to be the Achilles heel of previous attempts at electron projection lithography in vacuum. Monte Carlo simulations show that by using beryllium tritide thin film source in SPEL system, the exposure time can be reduced down to 2 min for each large-area (10000 cm(2) or more) parallel exposure, with resolution not larger than 20 nm. Moreover, experimental demonstration of large-area diameter-and-density controllable vertical NW arrays Fabricated by SPEL shows its promising utility for an application requiring large-area nanostructure definition.