Low temperature technology options for integrated high density capacitors

In recent years, integrated high-density capacitors have gained a lot of interest for RF and mixed signal IC applications. In this paper, we discuss technological options for integrated capacitors with capacitance densities up to 30fF/mum
²
. The capacitive structures where realized with dielectric materials such as Bi-Ta-O, Sr-Ta-O or Ta
₂
O
₅
. The Bi-Ta-O and Sr-Ta-O were deposited by means of metal organic chemical vapor deposition (MOCVD) at 360degC. Films with densities up to 30fF/mum
²
were obtained, the leakage current of the structures remained below 3.10
^-8
A/cm
²
at 3V for densities below 10 fF/mum
²
. In parallel, a dual dielectric layer process, with maximum fabrication temperature of 250degC, based on the anodic growth of Ta
₂
O
₅
was yielding devices with leakage current below 1.10
^-9
A/cm
²
at 3V for 9.5 fF/mum
²
capacitance density