Investigation of HfO_2 dielectrics for inter-poly dielectrics and metal-insulator-metal capacitors

摘要

We have investigated HfO_2 as dielectric of the Inter-Poly Dielectrics (IPDs) and Metal-Insulator-Metal (MIM) capacitors. The thickness of HfO_2 deposited in Metal-Organic-Chemical-Vapor-Deposition (MOCVD) is 20-nm, The 200nm-thick polysilicon is deposited in Low-Pressure-Chemical-Vapor-Deposition (LPCVD). The metals used in MIM capacitors are sputtered TiN and HfN. Experimental results show low leakage current of ～ 10~(-9) A/cm~2 and high dielectric constant of ～ 22 in MIM capacitors. The leakage current for IPDs is larger due to the roughness in polySi/HfO_2 interface, and the dielectric constant is reduced because of the interfacial layer. The temperature coefficient of the IPDs and MIM capacitors is very small.