Capacitor of semiconductor device and method for manufacturing the same

Abstract

Provided is a capacitor of a semiconductor device. The capacitor includes a capacitor lower electrode disposed on a semiconductor substrate. A first dielectric layer comprising aluminum oxide (Al 2 O 3 ) is disposed on the capacitor lower electrode. A second dielectric layer comprising a material having a higher dielectric constant than that of aluminum oxide is disposed on the first dielectric layer. A third dielectric layer comprising aluminum oxide is disposed on the second dielectric layer. A capacitor upper electrode is disposed on the third dielectric layer. The capacitor of the present invention can improve electrical properties. Thus, power consumption can be reduced and capacitance per unit area is high enough to achieve high integration.

1 . A method for manufacturing a capacitor of a semiconductor device, the method comprising: 
 forming a capacitor lower electrode on a semiconductor substrate;    forming a first dielectric layer comprising aluminum oxide on the capacitor lower electrode;    forming a second dielectric layer comprising a material having a higher dielectric constant than aluminum oxide on the first dielectric layer;    forming a third dielectric layer comprising aluminum oxide on the second dielectric layer;    forming a capacitor upper electrode on the third dielectric layer; and    thermally treating the resultant structure after forming the upper electrode.    
   
   
       2 . The method as claim in  claim 1 , wherein the second dielectric layer is formed of one selected from the group consisting of a Ta 2 O 5  layer, a Ti-doped Ta 2 O 5  layer, a TaO x N y  layer, a HfO 2  layer, a ZrO 2  layer, a Pr 2 O 3  layer, a La 2 O 3  layer, a SrTiO 3 (STO) layer, a (Ba, Sr)TiO 3 (BST) layer, a PbTiO 3  layer, a Pb(Zr, Ti)O 3 (PZT) layer, a SrBi 2 Ta 2 O 9 (SBT) layer, (Pb, La)(Zr, Ti)O 3  layer, and a BaTiO 3 (BTO) layer, and any combination thereof.  
   
   
       3 . The method of  claim 1 , further comprising performing a thermal treatment on the second dielectric layer after forming the second dielectric layer.  
   
   
       4 . The method of  claim 3 , wherein the thermal treatment is carried out in an atmosphere containing oxygen.  
   
   
       5 . The method of  claim 4 , wherein the thermal treatment is carried out in an atmosphere of O 3  gas, O 2  plasma gas, or N 2 O plasma gas.  
   
   
       6 . The method of  claim 4 , wherein the thermal treatment is carried out at a temperature of about 300° C. to about 500° C.  
   
   
       7 . The method as claim in  claim 1 , wherein the capacitor lower electrode or the capacitor upper electrode is formed of one selected from the group consisting of a doped polysilicon, a metal such as W, Pt, Ru, and Ir, a conductive metal nitride such as TiN, TaN, and WN, and a conductive metal oxide such as RuO 2  and IrO 2 , and any combination thereof.  
   
   
       8 . A method for manufacturing a capacitor of a semiconductor device, the method comprising: 
 forming a capacitor lower electrode on a semiconductor substrate;    forming a first dielectric layer comprising aluminum oxide on the capacitor lower electrode;    forming a second dielectric layer comprising a material having a higher dielectric constant than aluminum oxide on the first dielectric layer;    forming a third dielectric layer comprising aluminum oxide on the second dielectric layer;    forming a capacitor upper electrode on the third dielectric layer; and    thermally treating the resultant structure after forming the upper electrode,    wherein the first dielectric layer or the third dielectric layer is formed using a gas containing oxygen without hydrogen as a reactant gas.    
   
   
       9 . The method of  claim 8 , wherein the reactant gas comprises at least one of O 3  gas and O 2  gas.