A Difference in Using Atomic Layer Deposition or Physical Vapour Deposition TiN as Electrode Material in Metal-Insulator-Metal and Metal-Insulator-Silicon Capacitors

Abstract

In this work, metal-insulator-metal (MIM) and metal-insulator-silicon (MIS) capacitors are studied using titanium nitride (TiN) as the electrode material. The effect of structural defects on the electrical properties on MIS and MIM capacitors is studied for various electrode configurations. In the MIM capacitors the bottom electrode is a patterned 100 nm TiN layer (called BE type 1), deposited via sputtering, while MIS capacitors have a flat bottom electrode (called BE type 2-silicon substrate). A high quality 50-100 nm thick SiO2 layer, made by inductively-coupled plasma CVD at 150 degrees C, is deposited as a dielectric on top of both types of bottom electrodes. BE type 1 (MIM) capacitors have a varying from low to high concentration of structural defects in the SiO2 layer. BE type 2 (MIS) capacitors have a low concentration of structural defects and are used as a reference. Two sets of each capacitor design are fabricated with the TiN top electrode deposited either via physical vapour deposition (PVD, i.e., sputtering) or atomic layer deposition (ALD). The MIM and MIS capacitors are electrically characterized in terms of the leakage current at an electric field of 0.1 MV/cm (I leak) and for different structural defect concentrations. It is shown that the structural defects only show up in the electrical characteristics of BE type 1 capacitors with an ALD TiN-based top electrode. This is due to the excellent step coverage of the ALD process. This work clearly demonstrates the sensitivity to process-induced structural defects, when ALD is used as a step in process integration of conductors on insulation materials.

Highly-Conformal TiN Thin Films Grown by Thermal and Plasma-Enhanced Atomic Layer Deposition

“…6,7 Physical vapor deposition (PVD) suffers indeed from a poor step coverage and chemical vapor deposition (CVD) requires high temperatures processing. [8][9][10][11][12] Reversely, ALD provides an accurate control of the thickness and it allows to grow highly-conformal layers with a high quality at relatively low temperatures. 13 The surface chemical reaction involved during the ALD process can either be thermally activated by heating the reactor or it can be activated by generating a plasma in the chamber (plasma-enhanced ALD, PE-ALD).…”

New development of atomic layer deposition: processes, methods and applications

“…Atomic layer deposition on porous alumina membranes promises a path to produce high-performance capacitors [195]. Groenland et al [196] studied metal insulator silicon (MIS) and metal insulator metal (MIM) capacitors using titanium nitride. They applied the atomic layer deposition process in the integration of conductors on insulation materials.…”

Atomic Layer Deposition of TiN/Al2O3/TiN Nanolaminates for Capacitor Applications

“…It is used in a lot of energy storage applications [1] but also in many other fields such as memories or sensors [2]. The final goal of this study is to develop Metal-Insulator-Metal (MIM) systems [3,4,5]. These nanocapacitors are formed by three successive nanolaminates covering high aspect ratio nanostructures.…”