Electron beam lithography writing strategies for low loss, high confinement silicon optical waveguides

Abstract

The authors present a robust process for fabricating passive silicon photonic components by direct-write electron beam lithography (EBL). Using waveguide transmission loss as a metric, we study the impact of EBL writing parameters on waveguide performance and writing time. As expected, write strategies that reduce sidewall roughness improve waveguide loss and yield. In particular, averaging techniques such as overlap or field shift writing reduce loss, however, the biggest improvement comes from writing using the smaller field-size option of our EBL system. The authors quantify the improvement for each variation and option, along with the tradeoff in writing time. V

Compact Broadband Directional Couplers Using Subwavelength Gratings

“…A JEOL JBX-6300FS system, operating at 100keV energy, and with an 8nA beam current and a 500µm exposure field was used to perform electron beam lithography [22]. The samples were on 25mm squares diced from 150mm wafers.…”

Nanolithography Toolbox

“…Lines 18-29 initialize a variety of variables used to create the arrayed structures. The nested for loop (lines [31][32][33][34][35][36][37][38][39][40] iterates through diameters and separations between circular array elements. In the inner loop, a pitch is calculated in line 33.…”

Propagation loss in sub-wavelength grating waveguides

“…Waveguides were 500 nm wide and 220 nm high. Fabrication was done at the University of Washington Nanofabrication Facility (WNF) using E-Beam Lithography (EBL) [4], all measurements took place at the University of British Columbia (UBC) using our automated optical setup. Figure 1, shows the received optical spectra for the measured structures, different colours represent different lengths.…”