Integrated reference vacuum pressure sensor with atomic layer deposition coated input port

A method for fabricating a pressure sensor, the method comprising:

• forming a stress isolation member in contact with a substrate, wherein the stress isolation member and the substrate have a channel formed through the substrate and the stress isolation member;
• fabricating a sensor die, wherein the sensor die comprises a diaphragm having sensing circuitry formed thereon;
• mounting the sensor die to the stress isolation member, wherein a first side of the diaphragm is exposed to an opening of the channel;
• securing the stress isolation member, the substrate, and the sensor die in a housing having an input port, wherein the channel is positioned in the housing such that a pressure media entering the input port also enters the channel;
• coating surfaces of the stress isolation member and the substrate that are exposed to either the input port or the channel with an atomic layer deposition;
• electrically connecting the sensing circuitry to an external system;
• and
• sealing a second side of the sensor die within an environment having a known pressure, wherein the second side is hermetically isolated from the opening of the channel.