Temperature dependence of silicon nitride deposited by remote plasma atomic layer deposition

Abstract

We investigated the characteristics of silicon nitride (SiNx) thin films deposited by remote plasma atomic layer deposition (RPALD) using trisilyamine (TSA) and ammonia (NH3) plasma at low temperatures. Although the process window of SiNx thin films is 150–350 °C, considering the refractive index (RI), SiNx thin films deposited at 250–350 °C were focused on for analyses. All of the SiNx films were nearly stoichiometric, regardless of the deposition temperature. As the deposition temperature increased, the RI increased, while the hydrogen content decreased. The defect density also changed at higher deposition temperatures; as the deposition temperature increased, all of the trap densities increased because of the low‐hydrogen content in the SiNx thin films. The characteristics of the SiNx thin film deposited by RPALD could be controlled to adjust the defect density for charge trap flash memory applications by changing the deposition temperature.

Remote Plasma Atomic Layer Deposition of SiNx Using Cyclosilazane and H2/N2 Plasma

“…In the case of PEALD, the gas temperature is easily changed in accordance with the substrate temperature change, which in turn affects the density of gaseous species and the generation of plasma species. The RPALD allows flexible control of plasma composition and properties at the substrate's location, making it well-suited for process design [8,[16][17][18][19]. The ALD of SiN x , silicon chlorides (e.g., SiCl 4 , SiH 2 Cl 2 , and Si 2 Cl 6 ) have been studied as silicon precursors along with reactants such as NH 3 , NH 3 plasma, or N 2 H 4 .…”

Redeposition in plasma-assisted atomic layer deposition: Silicon nitride film quality ruled by the gas residence time

“…Redeposition in plasma-assisted atomic layer deposition: Silicon nitride film quality ruled by the gas residence time Harm C. M. Knoops, 1,2,a) K. de Peuter, 1 The requirements on the material properties and growth control of silicon nitride (SiN x ) spacer films in transistors are becoming ever more stringent as scaling of transistor structures continues. One method to deposit high-quality films with excellent control is atomic layer deposition (ALD).…”

“…[http://dx.doi.org/10.1063/1.4926366] Silicon nitride (SiN x ) is one of the most widely used thin-film materials in many areas such as semiconductor technology, photovoltaics, and displays-due to its unique combination of optical, electrical, mechanical, and chemical properties. 1 One of its key applications in semiconductor technology is as spacer films in transistors where the SiN x serves multiple roles such as a barrier film and masking material. For this application, the requirement of uniform material quality and film thickness throughout the device, independent of transistor pitch, is becoming ever more rigorous as miniaturization of the transistor structures continues.…”

“…[1][2][3][4][5][6] This is especially the case when low impurity levels and low wet-etch rates are required, combined with the need to be deposited at low substrate temperatures (<400 C) from halide-free precursors. 1 Similar as for other nitride ALD processes, plasmas can be used during the reactant step to increase the surface reactivity. 7 Nonetheless, even with the high reactivity of the plasma, long plasma times are required to avoid high impurity contents.…”

A Brief Review of Plasma Enhanced Atomic Layer Deposition of Si3N4

“…Similarly, Jang et al studied the temperature dependency of SiN x thin film properties such as surface roughness and refractive index [27]. Their results revealed that SiN x thin films deposited at lower temperatures showed lower defect density caused by high hydrogen content.…”