Capacitor in semiconductor device and method of manufacturing the same

Abstract

The present invention relates to a capacitor in semiconductor device and a method of manufacturing the same, wherein, owing to formation of a lower electrode and an upper electrode into a stack structure of a poly-silicon layer and an aluminum (Al) layer and formation of an alumina (Al 2 O 3 ) film as a dielectric film, the lower electrode is formed into a stack structure of the poly-silicon layer-aluminum (Al) layer, thus increasing a surface area of electrodes due to the absence of oxidation during annealing, and preventing degeneration of the device, and use of the dielectric film including a high-dielectric constant material layer enables reduction of the dielectric film's thickness. Accordingly, the present invention is capable of increasing capacitance, is capable of reducing leakage current and improving dielectric breakdown characteristics via internal formation of an MIM capacitor, and is capable of reducing production costs by performing a continuous process via use of a single piece of equipment.

1 . A capacitor of a semiconductor device, comprising:
 a semiconductor substrate having lower structures including a transistor and bit lines formed thereon;   a lower electrode including a stack structure of a polysilicon layer and a first aluminum layer formed on the semiconductor substrate;   a dielectric film including a high-dielectric constant material layer formed on the lower electrode; and   an upper electrode including a second aluminum layer formed on the dielectric film.   
   
   
       2 . The capacitor of  claim 1 , wherein the polysilicon layer comprises a doped silicon layer, an undoped silicon layer, or a stack structure of doped and undoped silicon layers. 
   
   
       3 . The capacitor of  claim 1 , wherein the polysilicon layer comprises a metastable polysilicon (MPS) layer. 
   
   
       4 . The capacitor of  claim 1 , wherein the dielectric film comprises an alumina film, a hafnium oxide film, or a tantalum oxide film. 
   
   
       5 . The capacitor of  claim 1 , wherein the dielectric film further comprises aluminum nitride (AlN). 
   
   
       6 . The capacitor of  claim 1 , wherein the upper electrode comprises a stack structure of the second aluminum layer and the polysilicon layer.