We developed a vacuum window made of high-resistivity silicon for integration into the DESHIMA receiver, which is installed on the ASTE telescope in the Chilean Atacama desert. DESHIMA is a spectrometer operating between 220 to 440 GHz and has 124 mm diameter vacuum window . To reduce the substantial reflections expected from the bare silicon we laser-ablated sub-wavelength structures (SWSs) over an optically active circular area with a diameter of 67 mm using an ultra-short pulsed laser. The measured average transmittance within the pass band and the transmittance at any frequency are above 0.9. The window has been subjected to an atmospheric pressure difference for 10 days with no apparent vacuum leak. In this presentation, we introduce the design, including the tradeoff of the material choices, the fabrication, and the evaluation of its performance. To our knowledge, this is the first vacuum window made of silicon with the SWS anti-reflection surface operating in this frequency, a fractional bandwidth exceeding 65\%, on an astronomical receiver at the observational site.