Tetragonal Phase Stabilization by Doping as an Enabler of Thermally Stable HfO2 based MIM and MIS Capacitors for sub 50nm Deep Trench DRAM

Abstract

We show for the first time that control of the crystalline phases of HfO2 by tetravalent (Si) and trivalent (Y,Gd) dopants enables significant improvements in the capacitance equivalent thickness (CET) and leakage current in capacitors targeting deep trench (DT) DRAM applications. By applying these findings, we present a MIM capacitor meeting the requirements of the 40 nm node. A CET < 1.3 nm was achieved at the deep trench DRAM thermal budget of 1000 degC