In this report, we describe the two different nickel oxide film formation processes for microbolometer application:
the heat treatment of nickel metal and the reactive sputtering. Nickel oxide films obtained by the heat treatment of nickel
show high TCR(about -3.2/°C) and low 1/f noise characteristic. The reactively sputtered nickel oxide films have the wide
range of resistivity according to the sputtering vacuum level, time, and O<sub>2</sub>/Ar gas partial pressure. The acquired TCR of
sputtered films are in the range of -1.4%/°C and -3.45%°C. And the 1/f noise parameter k, which shows the performance
between VOx and a-Si, is as low as 8.5×10<sup>-13</sup> at the TCR of -1.75%/°C. Acquired nickel oxide films were analyzed from
XRD, AFM methods, and etc. It is regarded that the resistivity variation of polycrystalline nickel oxide film comes from
nonstoichiometric property of nickel and oxygen atoms. We simulated the optic and membrane structure for predicting
the performance of a microbolometer with nickel oxide film. The estimated NETD(noise equivalent temperature
difference) for the 50μmx50μm size of pixel is NETD below 20mK.
Double Exposure Technology (DET) is one of the main candidates for expanding the resolution limit of current lithography tool. But this technology has some bottleneck such as controlling the CD uniformity and overlay of both mask involved in the lithography process. One way to solve this problem and still maintain the resolution advantage of DET is using spacers. Patterning with a spacer not only expands the resolution limit but also solves the problems involved with DET. This method realizes the interconnection between the cell and peripheral region by "space spacer" instead of "line spacer" as usually used. Spacer process involves top hard mask etch, nitride spacer, oxide deposition, CMP, and nitride strip steps sequentially. Peripheral mask was additionally added to realize the interconnection region. With the use of spacers, it was possible to realize the NAND flash memory gate pattern with less than 50nm feature only using 0.85NA (ArF).