Method for producing crystallographically textured electrodes for textured PZT capacitors

US6853535B2 · kind B2 · utility

Assignee

• RAMTRON INTERNATIONAL CORPORATION · US

Inventors

• Glen Fox · Colorado Springs, US
• Thomas E. Davenport · Colorado Springs, US

Key dates

• Filing date: Jul 3, 2002
• Grant date: Feb 8, 2005
• Expiry date: Oct 26, 2022

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10D1/682

Abstract

A bottom electrode structure and manufacturing method is described for producing crystallographically textured iridium electrodes for making textured PZT capacitors that enables enhanced ferroelectric memory performance. The use of seed layers originating from hexagonal crystal structures with {0001} texture provides a smooth surface for growth of {111} textured iridium, which exhibits the face-centered cubic (“FCC”) structure. This seeding technique results in {111} textured iridium with a small surface roughness relative to the film thickness. The highly textured iridium supports {111} textured PZT dielectric layer growth. Textured PZT exhibits enhanced switched polarization, reduced operating voltage and also improves the reliability of PZT capacitors used in FRAM® memory and other microelectronic devices.