Metal-insulator-metal capacitors with a chemical barrier layer in a lower electrode

Abstract

A metal-insulator-metal (MIM) capacitor includes a lower electrode, a dielectric layer, and an upper electrode. The lower electrode includes a first conductive layer, a chemical barrier layer on the first conductive layer, and a second conductive layer on the chemical barrier layer. The chemical barrier layer is between the first and second conductive layers and is a different material than the first and second conductive layers. The dielectric layer is on the lower electrode. The upper electrode is on the dielectric layer opposite to the lower electrode. The first and second conductive layers can have the same thickness. The chemical barrier layer can be thinner than each of the first and second conductive layers. Related methods are discussed.

1 . A metal-insulator-metal (MIM) capacitor comprising:
 a lower electrode comprising a first conductive layer, a chemical barrier layer on the first conductive layer, and a second conductive layer on the chemical barrier layer, wherein the chemical barrier layer is between the first and second conductive layers and comprises a different material than the first and second conductive layers;   a dielectric layer on the lower electrode; and   an upper electrode on the dielectric layer opposite to the lower electrode.   
   
   
       2 . The MIM capacitor according to  claim 1 , wherein the first and second conductive layers each comprise titanium nitride (TiN), tantalum nitride (TaN), tungsten nitride (WN), ruthenium (Ru), platinum (Pt), ruthenium oxide (RuO 2 ), and/or platinum oxide (PtO 2 ). 
   
   
       3 . The MIM capacitor according to  claim 1 , wherein the first and second conductive layers have a same thickness. 
   
   
       4 . The MIM capacitor according to  claim 1 , wherein the chemical barrier layer comprises polysilicon (poly-Si), polysilicon germanium (poly-SiGe), titanium (Ti), hafnium oxide (HfO 2 ), hafnium oxynitride (HfON), titanium oxide (TiO 2 ), and/or titanium oxynitride (TiON). 
   
   
       5 . The MIM capacitor according to  claim 4 , wherein the chemical barrier layer has a thickness of about 1 Å to about 50 Å. 
   
   
       6 . The MIM capacitor according to  claim 1 , wherein the chemical barrier layer is thinner than each of the first and second conductive layers. 
   
   
       7 . The MIM capacitor according to  claim 6 , wherein each of the first and second conductive layers has a thickness of about 10 Å to about 200 Å. 
   
   
       8 . The MIM capacitor according to  claim 7 , wherein the chemical barrier layer has a thickness of about 1 Å to about 50 Å. 
   
   
       9 . A metal-insulator-metal (MIM) capacitor comprising:
 a semiconductor substrate;   an interlayer insulating layer on the semiconductor substrate;   a conductive plug extending from a surface of the semiconductor substrate through the interlayer insulating layer;   a lower electrode on a portion of the interlayer insulating layer and the conductive plug;   an etch stopper on a portion of the interlayer insulating layer adjacent to opposite sides of the lower electrode;   a dielectric layer on the lower electrode and the etch stopper; and   an upper electrode on the dielectric layer opposite to the lower electrode, wherein:   the lower electrode comprises a first conductive layer, a chemical barrier layer on the first conductive layer, and a second conductive layer on the chemical barrier layer, and the chemical barrier layer is between the first and second conductive layers;   the chemical barrier layer comprises a different material than the first and second conductive layers; and   the chemical barrier layer is thinner than each of the first and second conductive layers.   
   
   
       10 . The MIM capacitor according to  claim 9 , wherein the conductive plug comprises doped polysilicon. 
   
   
       11 . The MIM capacitor according to  claim 10 , further comprising a metal silicide layer between the conductive plug and the lower electrode. 
   
   
       12 . The MIM capacitor according to  claim 9 , wherein the conductive plug comprises titanium nitride. 
   
   
       13 . The MIM capacitor according to  claim 9 , wherein the lower electrode has a cylindrical shape. 
   
   
       14 . The MIM capacitor according to  claim 9 , wherein the first and second conductive layers of the lower electrode each comprise titanium nitride (TiN), tantalum nitride (TaN), tungsten nitride (WN), ruthenium (Ru), platinum (Pt), ruthenium oxide layer (RuO 2 ), and/or platinum oxide layer (PtO 2 ). 
   
   
       15 . The MIM capacitor according to  claim 14 , wherein each of the first and second conductive layers has a thickness of about 10 Å to about 200 Å. 
   
   
       16 . The MIM capacitor according to  claim 9 , wherein the chemical barrier layer comprises polysilicon (poly-Si), polysilicon germanium (poly-SiGe), titanium (Ti), hafnium oxide (HfO 2 ), hafnium oxynitride (HfON), titanium oxide (TiO 2 ), and/or titanium oxynitride (TiON). 
   
   
       17 . The MIM capacitor according to  claim 16 , wherein the chemical barrier layer has a thickness of about 1 Å to about 50 Å. 
   
   
       18 . The MIM capacitor according to  claim 9 , wherein the dielectric layer comprises hafnium oxide (HfO 2 ), zirconium oxide (ZrO 2 ), lanthanum oxide (La 2 O 5 ), and/or tantalum oxide (Ta 2 O 5 ). 
   
   
       19 . The MIM capacitor according to  claim 9 , wherein the upper electrode and the first and second conductive layers comprise the same material.