(A) nano-meter gap fabrication technology using chemical-mechanical polishing and its applications

Abstract

In this dissertation we have proposed a nano-meter gap fabrication technology using Chemical-Mechanical Polishing (CMP) and oxidation (it is called ``CMP-machining``). The CMP-machining has several advantages as follows. (a) Oxidation process determines the gap distance. Thus, it is relatively easy to form electrode gaps with dimensions of nano-meter without sub-micron lithography equipments (0.18~0.25 μm). (b) Due to the nature of oxidation, it allows for good uniformity and reproducibility in the gap distance. (c) The gap distance can be easily controlled by the oxidation temperature or time. (d) It is simple process. And the CMP-machining technology can be widely used at many application areas, including electrostatic comb actuator for large force, capacitive accelerometer for high sensitivity, lateral field emission device (FED) for reducing turn-on voltage, low voltage tunneling unit, and so on. In lateral FED, narrow gap is very important for reducing the operating voltage. Thus, we have applied CMP-machining to the lateral FED. As a result, the fabricated lateral FED has good performances. With the sample, of which the gap distance of 2560Å, the turn-on voltage, at which the current is 1 nA, is about 4.1 V. And the emission current is high about 4.2 μA at the voltage of 20 V. The good linearity clearly shows the confirmation of the field emission in F-N plot. And we have integrated lateral FED with electrostatic comb actuator for measuring the characteristics of emission current with respect to the gap distance.