Metal-Insulator-Metal (MIM) Capacitors with integrated high-k dielectrics
Radio frequency (RF) and analog / mixed-signal (AMS) technologies present essential and critical technologies for the success of many semiconductor products [1]. Such technologies serve the rapidly growing wireless communications market. They depend on many materials systems, some of which are compatible with complementary metal oxide semiconductor (CMOS) processing, such as SiGe.
BiCMOS is the dominant process technology used for RF transceivers today and will remain so in the foreseeable future [2]. Applications are focused on low noise amplifiers, frequency synthesis and logic, voltage controlled oscillators, driver amplifier and filters. Long-term challenges for passive elements will include the need to integrate new materials in a cost-effective manner to realize the high quality factor Q inductors and the high-density metal-insulator-metal (MIM) capacitors with high-k dielectrics [3]. MIM capacitors can be used in RF circuits for coupling and bypass capacitance. MIM capacitors are integrated in the back end part of process flow. Therefore, the maximum temperature of deposition is restricted by the thermal budget of back end processes. As an example, a cross-sectional SEM micrograph of MIM capacitors in SiGe BiCMOS technology is shown in Fig.1 [4].
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Fig. 1: Cross section TEM image of an integrated metal – insulator – metal (MIM) capacitor (from Ref. [4]) |