| 摘要 |
A high surface area capacitor comprising a double metal layer (an electrode metal and barrier material) deposited on hemispherical grain (HSG) silicon, wherein a high dielectric constant (HDC) material is deposited over the double metal layer. The high surface area capacitor is complete with an upper cell plate electrode deposited over the HDC material. The double metal layer is preferably comprises one noble metal, such as platinum or palladium, for the electrode metal and an oxidizable metal, such as ruthenium, iridium, or molybdenum, for the barrier material. The noble metal, such as platinum metal, alone would normally allow oxygen diffusion into and oxidize any adhesion layer (making the adhesion layer less conductive) and/or undesirably oxidize any silicon-containing material during the deposition of the HDC material. Thus, the barrier metal is used to form a conducting oxide layer or a conducting layer which stops the oxygen diffusion. The HSG silicon provides an enhanced surface roughness that boosts cell capacitance. The HDC material, preferably BST or the like, is also used to boost cell capacitance.
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