RF-MEMS capacitive switches with high reliability

A radio frequency microelectromechanical system (RF-MEMS) capacitive switch moveable from an “off” position to an “on” position and comprising:

• a lower electrode comprising a RF signal path;
• a moveable metal membrane providing upper electrode, selected from the group consisting of
• (a) a RF ground and a direct current (DC) ground, said membrane positioned above said lower electrode, and said membrane being spaced from said lower electrode by an air gap in the off position;
• and
• (b) a RF ground and a direct current (DC) ground, positioned above said movable membrane;
• a dielectric layer comprising a “fast discharge diamond dielectric layer”, said layer being ultrananocrystalline diamond (UNCD), or nanocrystalline diamond (NCD), or microcrystalline diamond (MCD);
• said membrane contacting said dielectric layer when a voltage is applied across the lower and upper electrodes in the on position;
• said membrane cooperating with said dielectric layer and lower electrode to form a metal-insulator-metal (MIM) capacitor in the on position;
• and
• said RF-MEMS capacitive switch provides a reliable long-life switch that is operable for at least 100 billion cycles.

A radio frequency microelectromechanical (RF-MEMS) capacitive switch, moveable for a switching time from an “off ” position in an “off-state”to an “on” position in an “on-state”, comprising:

• a bottom electrode comprising metal providing an RF signal path;
• a moveable metallic membrane providing a top electrode, selected from the group consisting of
• (a) an RF ground and a direct current (DC) ground said membrane being less than about 0.4 μm thick, said membrane being spaced from said bottom electrode by an air gap of about 2 microns to about 10 microns resulting in a substantially insignificant capacitance relative to an operating frequency of said switch;
• (b) an RF ground and a direct current (DC) ground, positioned above said membrane;
• a dielectric film with “fast discharge characteristics, providing a “fast discharge diamond dielectric layer” with insulating characteristics on said bottom electrode, said “fast discharge diamond dielectric layer” comprising ultrananocrystalline diamond (UNCD), or nanocrystalline diamond (NCD), or microcrystalline diamond (MCD);
• said film having a discharging and recovery time substantially less than said switching time for substantially discharging an accumulated charge within 50 microseconds;
• said membrane contacting said “fast discharge diamond dielectric layer” when a voltage of about 30 volts to about 50 volts is applied across said top and bottom electrodes in the on state;
• said membrane cooperating with said “fast discharge diamonddielectric layer” and said bottom electrode to form a metal-insulator-metal (MIM) capacitor in the on state;
• and
• said RF-MEMS capacitive switch comprises a reliable long-life switch that is operable for more than 100 billion cycles.