Noise Spectra of Six Gey Bz:H Thermo-sensing Films for Micro-bolometers

Abstract

AbstractNoise spectra in plasma deposited SixGeyBz:H thermo-sensing films for micro-bolometers have been studied. The samples were characterized by SIMS (composition) and conductivity (room temperature conductivity, activation energy) measurements. The noise spectra were measured in the temperature range from T= 300 K to T=400 K and in the frequency range from f=2 Hz to f=2×104 Hz. The noise spectra SI(f) for the samples Si0.11Ge0.88:H and Si0.04Ge0.71B0.23 can be described by SI(f) ˜ f– β with β = 1 and β = 0.4, respectively. For the sample Si0.06Ge0.67B0.26 two slopes were observed: in low frequency region f≤ 103 Hz β1= 0.7 and at higher frequencies f>103 Hz β2= 0.13. Increasing temperature resulted in an increase of noise magnitude and a change of β values. The latter depended on film composition. The correlation observed between noise and conductivity activation energies suggests that noise is due to bulk rather than interface processes. Noise spectrum of the thermo-sensing film Si0.11Ge0.88:H was compared with that for micro-bolometer structure with the same thermo-sensing film. The micro-bolometer structure showed higher noise value in entire frequency range that assumed additional processes inducing noise.