We describe the fabrication of high-stress Si_3N_4 nanobeam resonators with high aspect ratios exceeding lengths of 3.5mm. The lowest order out-of-plane modes of these nanobeams have quality factors of Q\geq 10^6 with fundamental mode frequencies lying in the range of 80-500kHz. The beams are fabricated from high-stress, 20-50nm-thick films of Si_3N_4 deposited via LPCVD on standard silicon wafers. The beams are patterned via electron beam lithography and deep reactive ion etching. The underlying silicon is ...
