A simple technique for creating trench structures in silicon using readily available wafer processing techniques is discussed. By using orientation dependent etching of (110) Si, it is possible to create trenches in silicon with vertical sidewalls. The etching anisotropy of certain solutions used with this technique is greater than 600:1 [110]:[111]etching, making it possible to fabricate virtually any value of aspect ratio trench. For this technique, which makes use of two etchants, an anisotropy of 50:1 is demonstrated. The equipment, materials, and processing steps required are outlined.