Grain size of polycrystalline silicon was studied for the use of resistive material of a micro-bolometer with a large TCR (Temperature Coefficient of Resistance) and low 1/f noise. Previous investigation showed that the large grain size increases TCR. Two methods were used for making polycrystalline silicon film: Solid Phase Crystallization (SPC), and Seed Selection Ion Channeling (SSIC). 4800 Å and 1400 Å thick polycrystalline silicon films were deposited and silicon ion implantations were performed through the films: doses of $2e15/1e16cm^{-2}$ ions with the energy of 50/150KeV for SPC film and dose of $1.2e15cm^{-2}$. ions with the energy of 280KeV for SSIC film, respectively.
Subsequently, grain growth was done in a furnace at 530 ℃ for 222 hours. Then boron ion implantation doses ranging from $2.0 * 10^9$ to $6.5 * 10^9 cm^{-2}$ into the polycrystalline silicon films were done and interlayer oxide was deposited, patterned, and p+ (boron) diffusion was done to make low contact resistance. Aluminum was deposited and patterned to measure I-V curve, resistivity, and 1/f noise. In this work, fabricated grain size was approximately 900 Å (SPC), 650 Å (As-deposited), and 480 Å (SSIC) by I-V measurements.
SPC film had the largest TCR due to large grain polycrystalline silicon and SSIC film had a low 1/f noise due to improved (220) crystallinity despite the small grain size. High detectivity up to $6.4 * 10^9 [cmHz^{1/2}/W]$ at the bias voltage of 2.5V was obtained from SSIC film due to preferred (220) grain orientation of the film. Polycrystalline silicon resistor with large grains made by SSIC method with higher silicon ion dose and low boron dose is expected to be the best CMOS compatible material for a bolometer resistor requiring for high TCR and low 1/f noise.