Tantalum capacitor

About: Tantalum capacitor is a research topic. Over the lifetime, 2432 publications have been published within this topic receiving 26709 citations.

Tantalum thin film capacitor

Abstract: A tantalum film capacitor has an α-tantalum as a lower electrode, a chemical conversion layer of α-tantalum as a dielectric and an upper electrode, an improvement involving forming a highly nitrogen-doped tantalum film between the α-tantalum and a substrate, and also, another improvement involving forming a transitional thin tantalum layer between said highly nitrogen-doped tantalum film and said α-tantalum. The nitrogen concentration of the highly nitrogen-doped tantalum film is from 14 to 30 atomic %. The electrical properties, especially leakage current, are improved over those of the prior art. A disadvantage of the conventional α-tantalum thin film capacitor, that is the necessity of using an expensive partial glazed Al2 O3 substrate, is eliminated, and a non-glazed Al2 O3 substrate can be used in the present invention.

Method for fabricating a flexible interconnect film with resistor and capacitor layers

Abstract: A method for fabricating a flexible interconnect film includes applying a resistor layer over one or both surfaces of a dielectric film; applying a metallization layer over the resistor layer with the resistor layer including a material facilitating adhesion of the dielectric film and the metallization layer; applying a capacitor dielectric layer over the metallization layer; and applying a capacitor electrode layer over the capacitor dielectric layer. The capacitor electrode layer is patterned to form a first capacitor electrode; the capacitor dielectric layer is patterned; the metallization layer is patterned to form a resistor; and the metallization layer and the resistor layer are patterned to form an inductor and a second capacitor electrode. In one embodiment, the dielectric film includes a polyimide, the resistor layer includes tantalum nitride, and the capacitor dielectric layer includes amorphous hydrogenated carbon or tantalum oxide. If the resistor and metallization layers are applied over both surfaces of the dielectric film, passive components can be fabricated on both surfaces of the dielectric film. The dielectric film can have vias therein with the resistor and metallization layers extending through the vias. A circuit chip can be attached and coupled to the passive components by metallization patterned through vias in an additional dielectric layer.

Film capacitors with improved dielectric properties

Abstract: A film capacitor (10) including a first electrode (12) is provided. The film capacitor (10) also includes a first dielectric layer (14) having a first dielectric constant disposed upon a first electrode (12) and a second dielectric layer (16) having a second dielectric constant disposed upon the first dielectric layer (14), wherein the second dielectric constant is at least fifty percent greater than the first dielectric constant. It further includes a second electrode disposed upon the second dielectric layer (16).

The modern era of aluminum electrolytic capacitors

Abstract: The first article in this series [1] covered the early history of electrolytic capacitors, from their invention around 1880 to the invention of the modern Al electrolytic capacitor structure in 1925. To summarize the early history, "valve metals" were recognized in the 1880s for their ability to conduct in one direction but impede current flow in the opposite direction as a result of oxide growth when submersed in an appropriate electrolyte. Early attempts to use the oxide as a dielectric so formed were frustrated by acidic electrolytes, which damaged the oxide layer and resulted in short capacitor life. Charles Pollak, a manufacturer of rechargeable batteries, realized the importance of the electrolyte and found that a neutral or basic electrolyte provides much greater stability of the oxide layer. In his 1896 German patent application for an electrolytic capacitor, Pollak described his invention as a "liquid condenser with aluminum electrodes, which are covered with a uniformly insulating layer generated by forming with a weak current, characterized by using an alkaline or neutral electrolyte. Since the insulating layer is very thin, the condenser has a very high capacitance and could be used as a polarized capacitor in a DC circuit." Early electrolytic capacitors consisted of an Al electrode in a "bath" of electrolyte. The resistance of the electrolyte resulted in a relatively high equivalent series resistance (ESR), and the capacitors were both bulky and heavy, although not relative to the alternatives at the time. Mains-operated radio receivers, introduced around 1927, created a large consumer market for capacitors, which were required to produce ripple-free DC voltages. Wax paper capacitors, limited to 1 or 2 μF, had to be combined with bulky chokes (inductors) to produce efficient power frequency filters. Electrolytic capacitors provided much greater capacitance so that the chokes were not necessary, but early electrolytic capacitors used in radio receivers still consisted of an oxidized anode in a bath of electrolyte.

Transistor and a capacitor used for forming a vertically stacked dynamic random access memory cell

Abstract: A transistor and a capacitor is used to provide, in one form, a dynamic random access memory (DRAM) cell (10). The capacitor of cell (10) lies within a substrate (12). The capacitor has a first capacitor electrode (16) and a second capacitor electrode (20). A dielectric layer (18) is formed as an inter-electrode capacitor dielectric. A first transistor current electrode (36) is formed overlying and electrically connected to the first capacitor electrode (16). A channel region (38) is formed overlying the first transistor current electrode (36). A second transistor current electrode (40) is formed overlying the channel region (38). A conductive layer (30) is formed laterally adjacent the channel region (38) and isolated from the substrate (12) by dielectric layers (22 and 28). A conductive layer (30) functions as a gate electrode for the transistor and a sidewall dielectric (34) functions as a gate dielectric. The combination of a cylindrical dual-sidewall surface area capacitor for a large capacitance, along with a vertical transistor physically overlying the capacitor, forms a very dense and efficient DRAM structure.