The MIM capacitors with HfO2 and HfAlOx are investigated for Si RF and analog applications. The results show that both the capacitance density and voltage coefficients of capacitance (VCCs) increase with decreasing the HfO2 thickness. A high capacitance density of 13 fF/μm2with a low leakage current and a VCC of 607 ppm/V is obtained for 10 nm HfO2 MIM capacitor, which can meet the requirement of the ITRS roadmap by 2007 for silicon RF application. On the other hand, it was found that both the capacitance density and voltage coefficients of capacitance (VCC) values of the HfAlOx MIM capacitors decrease with increasing Al2O3 concentration. The results show that HfAlOx MIM capacitor with an Al2O3 mole fraction of 0.14 is optimized. It provides a high capacitance density of 3.5 fF/μm2 and a low VCC of μ140 ppm/V2. Also, small frequency dependence, low leakage current, and low loss tangent are obtained. Thus, the HfAlOx MIM capacitor with an Al2O3 mole ratio of 0.14 is very suitable for use in silicon analog applications.