Decoupling Capacitors

Shown is a BST capacitor chip made on a silicon wafer used in one of Sound Design Technologies' hearing aid modules. It integrates 18 decoupling capacitors onto a single chip measuring 3mm x 5mm. The capacitors range in value from 440pF to 150nF. An integrated routing layer provides the circuitry used to interconnect certain elements of the capacitor array and to form I/O pads.





The high capacitance density that BST offers results in very small electrode sizes which minimizes series inductance, resulting in a comparatively high self-resonant frequency. The small electrodes also reduce the series resistance enabling high quality decoupling well into the GHz range.

By flip chipping an IC(s) directly onto the capacitor chip parasitics can be minimized further enhancing system performance.





LC Networks

Sound Design Technologies also offers nitride based capacitors integrated with high quality inductors to form LC networks. The low k dielectric materials and thick metal layers provide high Q values while still being real estate efficient. A wide range of high precision capacitor and inductor networks needed for high frequency applications can fabricated on the same chip. Applications include GSM and other cellular bands such as Bluetooth (2.45GHz) and WLAN (5 GHz).

Shown is a customized RF passive component used for a Bluetooth application. The component features a 2.45 GHz bandpass filter, 180 degree balun, loop filter capacitor, and an array of decoupling capacitors and matching networks.

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To download a pdf summary sheet for the BST integrated thin-film capacitor process click here