Methods of forming low leakage currents metal-insulator-metal (MIM) capacitors and related MIM capacitors

An MIM capacitor, comprising:

• a lower electrode on a semiconductor substrate;
• a lower dielectric layer having a thickness of about 20 to 40 Angstroms on the lower electrode, the lower dielectric layer having a first dielectric constant and a first energy band gap;
• an upper dielectric layer having a thickness of about 10 to 60 Angstroms on the lower dielectric layer, the upper dielectric layer having a second dielectric constant and a second energy band gap;
• wherein the second dielectric constant is higher than the first dielectric constant and the second energy band gap is smaller than the first energy band gap;
• and
• an upper electrode on the upper dielectric layer, the upper electrode comprising a noble metal that has a higher work function than a work function of the lower electrode.

An MIM capacitor, comprising:

• a lower electrode on a semiconductor substrate;
• a lower dielectric layer on the lower electrode, the lower dielectric layer having a first dielectric constant and a first energy band gap;
• an upper dielectric layer on the lower dielectric layer, the upper dielectric layer having a second dielectric constant and a second energy band gap;
• wherein the second dielectric constant is higher than the first dielectric constant and the second energy band gap is smaller than the first energy band gap;
• and
• an upper electrode on the upper dielectric layer, the upper electrode comprising a noble metal that has a higher work function than a work function of the lower electrode.