Low-Pressure SDS Gas Sources

The company offers the Type 850 Mini-Baratron pressure transducer, Type M330 thermal-based mass flow controller (MFC), and Type 1640 pressure-based MFC to optimize the value of low-pressure SDS (Safe Delivery Source) gas sources in implant or CVD processes. With such a wide dynamic pressure range from 3000 psi down to vacuum, the 850 pressure transducer accurately and reliably measures the SDS source pressure from full to empty. The source pressure is a measure of the amount of remaining gas and can be used to determine when a source cylinder change is needed. Because the 850 can accurately measure in the critical low-pressure range with 1% or reading accuracy, aborted implants due to unexpected loss of gas flow are prevented, and premature, costly cylinder change-outs are avoided.

The company offers a choice of mass flow technology with either the Type M330 thermal-based MFC or the Type 1640 pressure-based MFC. Both have the extremely low pressure drop and can operate at pressure differentials as low as 5 Torr to achieve gas cylinder utilization of 90% or better. The pressure drop across the MFC is a measure of the amount of valuable gas remaining in the cylinder and determines the gas utilization that can be achieved. For example, for a pressure drop across the MFC of 50 Torr, the gas utilization is about 65%. Reducing the pressure drop to 5 Torr increases the utilization to over 90%, minimizing the amount of valuable gas remaining in the cylinder. SDS gas sources are used as replacements for high-pressure gas cylinders to safely introduce dopant gases such as phosphine and arsine into ion inplant or CVD systems. The SDS contains gas absorbed onto a solid material and operates at or below atmospheric pressure. The pressure range from full to "empty" is typically 760 Torr sown to 5^-10 Torr.

MKS Instruments, 6 Shattuck Rd., Andover, MA 01810. Tel: 800-227-8766 or 978-975-2350. Fax: 978-975-0093.