Detailed leakage current analysis of metal–insulator–metal capacitors with ZrO2, ZrO2/SiO2/ZrO2, and ZrO2/Al2O3/ZrO2 as dielectric and TiN electrodes

Abstract

ZrO2-based metal–insulator–metal capacitors are used in various volatile and nonvolatile memory devices as well as for buffer capacitors or radio frequency applications. Thus, process optimization and material tuning by doping is necessary to selectively optimize the electrical performance. The most common process for dielectric fabrication is atomic layer deposition which guarantees high conformity in three dimensional structures and excellent composition control. In this paper, the C–V and J–V characteristics of ZrO2 metal–insulator–metal capacitors with TiN electrodes are analyzed in dependence on the O3 pulse time revealing the optimum atomic layer deposition process conditions. Moreover, a detailed study of the leakage current mechanisms in undoped ZrO2 compared to SiO2- or Al2O3-doped ZrO2 is enclosed. Thereby, the discovered dependencies on interfaces, doping, layer thickness, and crystalline phase's enable the detailed understanding and evaluation of the most suitable material stack for dynamic random access memory devices below the 20 nm generation.

Controlling the Electrical Characteristics of ZrO2/Al2O3/ZrO2 Capacitors by Adopting a Ru Top Electrode Grown via Atomic Layer Deposition

“…The obtained φ 0 and ϵ ∞ from Figure (c) and (d) were 0.63 eV and 7.15 for the positive‐bias‐applying case, and 0.73 eV and 6.85 for the negative‐bias‐applying case. The optical dielectric constant were slightly higher than the theoretical value but were still consistent with the previous studies . The same J–V data were also fitted to the Schottky emission mechanism, but the extracted barrier height and optical dielectric constant values were unreasonable (1.79 eV and 0.57, respectively.)…”

“…To investigate the leakage conduction mechanism in the 1–2 MV cm −1 electric field region, which is the relevant region for the most critical 4.6 nm‐thick films near 0.8 V, the J–V characteristics of the TiN TE sample under both positive and negative biases were measured at temperatures ( T ) ranging from 303 to 363 K, and the results are shown in Figure (a) and (b). It can be seen that the TiN TE sample showed a large increase in J , with the increasing T suggesting the operation of a certain thermionic‐emission mechanism, such as the Poole–Frenkel (P‐F) emission or Schottky conduction mechanism . The J–V curves of the TiN TE sample were replotted according to P‐F emission Equation .…”

Physical Mechanisms behind the Field‐Cycling Behavior of HfO2‐Based Ferroelectric Capacitors

“…These interfacial regions consist of nonswitching transitional material (TM-HfO 2 ) ( Figure 5) and are parasitically grown during the deposition of the HfO x and the subsequent annealing step. [39,40] During deposition of the HfO 2 dielectric atop of TiN bottom electrode, a TiO x N y interfacial layer is formed, which pulls oxygen out of the HfO 2 whereas nitrogen diffuses into the dielectric. [39,40] Moreover, an additional growth of the bottom interface layer was reported during top electrode deposition, [39,40] which creates further asymmetry within the device.…”

A Technology-Computer-Aided-Design-Based Reliability Prediction Model for DRAM Storage Capacitors

“…The leakage currents of ZrO 2 -based storage capacitors are affected mainly by PFE and TAT owing to the high defect density of ZrO 2 [13,14]. In addition to the PFE and TAT, the proposed model solved the electron and hole continuity equations coupled with the Poisson equation:∇·(ε∇ϕ)=−q(p−n+ND−NA)−ρtrap ∇·Jfalse→n=q(Rnet,normaln−Gnet,normaln)+q∂n∂t −∇·Jfalse→p=q(Rnet,normalp−Gnet,normalp)+q∂p∂t where ε is the electrical permittivity, q is the elementary electronic charge, N D is the concentration of ionized donors, N A is the concentration of ionized acceptors, ρtrap is the charge density contributed by traps, R net,n and R net,p are the electron and hole net recombination rates, G net,n and G net,p are the electron and hole net generation rates, Jfalse→n…”