dc.description.abstract | This research is using integrated-circuit(IC)photolithography to manufacture the structure of interconnect via in silicon wafer. We use microwave plasma chemical vapor deposition(MPCVD)to grow carbon nanotubes(CNTs)in the via to control the growth of vertically in-situ carbon nanotubes and achieve replacing the metal in the via with CNTs. We design a single-via and array-via in the same region with three different metals(Ti, Ta and Al)bottom electrode. Finally, we deposit the top electrode with Ti, Ta or Al to connect with CNTs to form CNT diode structure. Then we use SEM, Raman spectroscopy, and I-V system to analysis diode structure. We discuss the effect of process parameters on the properties and the diode resistances of CNTs in single and array via, and compare the conductive performance of diode with Ti , Ta and Al bottom electrode.
This research is using low temperature manufacture to match up the IC manufacture and aluminum melting point. The temperature which we selected from 350℃ to 500 ℃ and we use bias to increase the growth of CNTs. From the result, We find that multi-wall carbon nanotube(MWNT) diameter decreases with increase of substrate temperature and bias; and the degree of graphitization of MWNTs increases with the increase of substrate temperature and bias. Consequently, the diode resistance of MWNTs in both single and array vias decreases with the increase of MWNT graphitization. In the same via region, the MWNT diode resistances of the array vias are lower than those of the single vias; the MWNT diode resistances with the Ti bottom electrode are lower than those with the Ta or Al bottom electrode. And we also select diffecent top electrode with Ti, Ta and Al, and then compare it. The diode resistance with Ti top electrode are almose the same with Ta top electrode and lower with Al top electode. Thus, in this research we use Ta top electode and Ti bottom electode, PP: 1200 W, PG: 1200 W, Temp. : 500 ℃, CH4 flow ratio: 30%, and bias: 200 Volt, we measure the best degree of graphitization (38%) and the lowest MWNT diode resistance (71 Ω). | en_US |