Reactive Ion Etching of Lead Zirconate Titanate (PZT) Thin Film Capacitors

Abstract

One of the key processing concerns in the integration of PbZrxTi1−xO3false(PZTfalse) thin film capacitors into the existing VLSI for ferroelectric or dynamic random access memory applications is the patterning of these films and the electrodes. In this work, we have identified a suitable etch gas false(CCl2F2false) for dry etching of PZT thin films on RuO2 electrodes. The etch rate and anisotropy have been studied as a function of etching conditions. The trends in the effect on the etch rate of the gas pressure, RF power and O2 additions to the etch gas have been determined and an etching mechanism has been proposed. It was found that ion bombardment effects are primarily responsible for the etching of both PZT and RuO2 thin films. Etch rates of the order of 20–30 nm/min were obtained for PZT thin films under low gas pressure and high RF power conditions. The etch residues and the relative etch rates of the components of the PZT solid solution were determined using XPS. The results show that the etching of normalPbO is the limiting factor in the etch process.

A Novel Wet Etching Process of Pb(Zr,Ti)O3 Thin Films for Applications in Microelectromechanical System

“…In order to improve the etch selectivity of PZT over the photoresist and Pt bottom electrode, considerable attention has been paid to the RIE process for PZT thin films. 10,11) However, chemical contaminations during the RIE process are likely to deteriorate the surface roughness and degrade the properties of etched PZT films. 12) Although high-density plasma systems, such as inductively coupled plasma (ICP) 13) and electron cyclotron resonance (ECR), 14) can be employed to increase the etching rate of RIE, these methods are still unsatisfactory to meet the demands of device fabrication processes for achieving high quality PZT patterns.…”

A priori estimates, existence and non-existence for quasilinear cooperative elliptic systems

“…[6][7][8][9] In gigabit DRAMs, threedimensional capacitors will be necessary even if BST is used as a capacitor dielectric. 10) Therefore, chemical vapor deposition (CVD) is considered to be an essential film preparation method for both Ru electrodes and capacitor dielectrics.…”

Fine patterning of ceramic thick layer on aerosol deposition by lift-off process using photoresist

“…Various etching processes, such as wet etching [1], ion beam etching [2], reactive ion beam etching [3], plasma etching [4], and reactive ion etching (RIE) [5][6][7], have been studied to define the patterns on ferroelectric materials such as lead zirconium titanate (PZT) and lead lanthanum zirconate titanate thin films. However, fine patterning of ceramic thick layer over 1 µm thickness is not easy because etching ratio of ceramic layer is generally very low even when inductively coupled plasma (ICP)-RIE, known for its high etching rates, is used [8][9][10].…”