Thermally Isolated PbTiO3 Uncooled Focal Plane Array Detector

Infrared sensors and sensor arrays are widely used in military and commercial applications such as night vision, medical diagnosis and weather mapping. Expensive quantum effect sensors, such as HgCdTe systems, must be cooled to liquid nitrogen temperatures and are difficult to produce with uniform properties. A significant opportunity exists to dramatically improve detector fabrication and performance by employing thin film pyroelectric materials for the detector element. While encouraging pyroelectric properties have been reported in several ferroelectric materials, PbTiO3 is advantageous because of its high pyroelectric coefficient (40-90 nC/cm2.K at 297K), high Curie temperature (490 degrees C), mechanical and chemical resistance. PbTiO3 can be deposited in thin film form. However, unless thermal mass is minimized, pyroelectric sensitivity is severely reduced. ATM proposes to develop a thermally isolated micro air-bridge device using a novel MOCVD technique for PbTiO3 growth that will not only produce high pyroelectric sensitivity material, but also lead itself to c-axis oriented, high density array fabrication on a manufacturing scale with significantly reduced Pb toxicity hazards. The Phase II program will address fabrication and integration of high density detector arrays on silicon substrates containing CMOS circuitry.