Monolithically integrated switched capacitor bank using micro electro mechanical system (MEMS) technology

A monolithically integrated switched capacitor bank, comprising:

• a substrate;
• a pair of output signal lines on said substrate that terminate at respective output terminals;
• and
• a plurality of series-connected micro electro mechanical system (MEMS) switch-capacitor pairs on said substrate that are connected in parallel between the pair of output signal lines, each said MEMS switch switching in response to a control signal to connect and disconnect its capacitor to set a total capacitance seen at said output terminals to one of a plurality of levels, each of said MEMS switch-capacitor pairs comprising:
• a bottom electrode and a switch signal line formed on the substrate, said switch signal line having a first end that is connected to one of said output signal lines, a second end, and a gap forming an open circuit;
• a cantilever arm formed of insulating material affixed to said substrate and suspended above said bottom electrode and said gap in said switch signal line;
• an electrical contact formed on said cantilever arm positioned facing said gap in said switch signal line;
• a top electrode formed atop said cantilever arm, a portion of said cantilever arm and said top electrode positioned above said bottom electrode forming a first capacitor structure that is electrostatically attractable toward said bottom electrode upon selective application of a voltage to said top electrode;
• a pair of capacitor anchor structures formed on said substrate, one said capacitor anchor structure being electrically connected to the second end of said switch signal line and the other capacitor anchor structure being electrically connected to the other said output signal line;
• and
• a pair of capacitor electrodes that are connected to the respective capacitor anchor structures to form a second capacitor structure,
• said electrostatic attraction of said first capacitor structure toward said bottom electrode causing said electrical contact on said cantilever arm to close said gap in said switch signal line thereby connecting said second capacitor structure between said output terminals.

A monolithically integrated switched capacitor bank, comprising:

• a substrate;
• a pair of output signal lines on said substrate that terminate at respective output terminals;
• and
• a plurality of series-connected micro electro mechanical system (MEMS) switch-capacitor pairs on said substrate that are connected in parallel between the pair of output signal lines, each said MEMS switch switching in response to a control signal to connect and disconnect its capacitor to set a total capacitance seen at said output terminals to one of a plurality of levels, each said MEMS switch-capacitor pair, comprises:
• a bottom electrode and a switch signal line formed on the substrate, said switch signal line having a first end that is connected to one of said output signal lines, a second end, and a gap forming an open circuit;
• a cantilever arm formed of insulating material affixed to said substrate and suspended above said bottom electrode and said gap in said switch signal line;
• an electrical contact formed on said cantilever arm positioned facing said gap in said switch signal line;
• a top electrode formed atop said cantilever arm, a portion of said cantilever arm and said top electrode positioned above said bottom electrode forming a first capacitor structure that is electrostatically attractable toward said bottom electrode upon selective application of a voltage to said top electrode;
• a pair of capacitor anchor structures formed on said substrate, one said capacitor anchor structure being electrically connected to the second end of said switch signal line and the other capacitor anchor structure being electrically connected to the other said output signal line;
• and
• a pair of capacitor electrodes that are connected to the respective capacitor anchor structures and suspended above the substrate to form a second capacitor structure whose parasitic capacitance to said substrate is low,
• said electrostatic attraction of said first capacitor structure toward said bottom electrode causing said electrical contact on said cantilever arm to close said gap in said switch signal line thereby connecting said second capacitor structure between said output terminals.

A monolithically integrated switched capacitor bank, comprising:

• a substrate;
• a pair of output signal lines on said substrate that terminate at respective output terminals;
• and
• a plurality of series-connected micro electro mechanical system (MEMS) switch-capacitor pairs on said substrate that are connected in parallel between the pair of output signal lines, each said MEMS switch switching in response to a control signal to connect and disconnect its capacitor to set a total capacitance seen at said output terminals to one of a plurality of levels, each said MEMS switch-capacitor pair, comprises:
• a patterned first metal layer on said substrate that defines a first bottom electrode, and a switch signal line on the substrate, said switch signal line having a first end that is connected to one of said output signal lines, a second end, and a gap forming an open circuit;
• a patterned second metal layer that defines an electrical contact suspended above said substrate facing said gap in said switch signal line and to define a second bottom electrode that is anchored to and suspended above said substrate;
• a patterned oxide layer that defines a cantilever arm that is anchored to said substrate and suspended above said bottom electrode and said gap in said switch signal line to support said electrical contact and to define a dielectric spacer layer over said second bottom electrode;
• and
• a patterned third metal layer on said oxide layer that defines first and second top electrodes above the first and second bottom electrodes, respectively, said first top and bottom electrodes forming a first capacitor structure that is electrostatically attractable toward said bottom electrode upon selective application of a voltage to said top electrode, said second top and bottom electrodes forming a second capacitor structures whose parasitic capacitance to said substrate is low,
• said electrostatic attraction of said first capacitor structure toward said bottom electrode causing said electrical contact on said cantilever arm to close said gap in said switch signal line thereby connecting said second capacitor structure between said output terminals.