Abstract: A multi-port gas injector for a vertical furnace that is utilized for low-pressure chemical vapor deposition of silicon dioxide using a tetraethyl orthosilicate (“TEOS”) source is provided. The multi-port gas injector has two or three ports for introducing TEOS into the vertical furnace. The gas injector includes a first and second section of tubing, preferably made of quartz, joined such that they are preferably substantially perpendicular. One end of the second section forms one of the ports. In one embodiment a hole located at the position where the first and second sections are joined forms a second port. In other embodiments, a third and, possibly, a fourth section of tubing are joined to the second section of tubing to form a second and, possibly, a third port. Additionally, the second section of tubing may have one or more tapers to reduce the diameter of the hole through which gas exits.