Noise Reduction Of SixGe1-x and SixGe1-xOy Bolometers by Forming Gas PassivationMukti Rana and Donald ButlerUniversity of Texas at ArlingtonElectrical Engineering Dept.Arlington, TX 76019

Based in part by work supported by the National Science FoundationECS-0322900

BolometerBolometers are the optical sensors whose resistivity varies with temperature. When lights fall on the bolometer surface the sensing material of the bolometer absorbs heat and there by changes its resistance.

Why Noise Reduction is importantNoise detoriates the Bolometers performance by reducing the detectivity, responsivity.Amorphous films are characterized by higher noise.

Bolometer Fabricationp-Si Substrate Ni PadAl MirrorSiN Insulation LayerPI 2737 Sacrificial LayerNi ContactSiNNiCr ArmSiGeONiCr AbsorberSiNAshing of PI2737 in Oxygen Plasma

Micormacined Bolometer : SEM Picture

Experimental Details of Forming Gas PassivationThe Bolometers noise was measured in a shielded probe station with the help of SRC560 low noise preamplifier, HP 3562 dynamic signal analyzer and a computer. The noise spectra of same device was measured before and after the passivation to compare the noise. An AXIC Jet First Rapid Thermal Anneal (RTA) was used for annealing the sample. The sample was kept inside the chamber at a forming gas flow of 500 SCCM for different intervals of time.

Results: Noise Voltage Power Spectral Density (PSD) at 0.6uA Bias Current of SiGeO Bolometer Before and After Forming Gas Passivation