New Stacked Metal–Insulator–Metal Capacitor with High Capacitance Density for Future InP-Based ICs

Increasing the capacitance density would be a very effective way of making InP IC chips smaller because capacitors occupy a large area of InP IC chips. In this study, as a way of increasing capacitance density, we propose new stacked metal–insulator–metal (MIM) capacitors that can be fabricated by using only two additional masks alternately and repeatedly. The capacitors can also be fabricated with a short turn-around time by forming side contact via, which allows each MIM electrode to connect to each other electrically all at once. In the proposed capacitors with five stacked layers, the capacitance density increases by a factor of 5, from 0.30 to 1.47 fF/µm2, when 175-nm-thick SiN is used. The leakage current level is the same as that of a single-layer MIM capacitor.