MOS Capacitance Measurements for PEALD TiO2 Dielectric Films Grown under Different Conditions and the Impact of Al2O3 Partial-Monolayer Insertion

Author(s)

Chiappim, William ^{[1, 2]} ; Watanabe, Marcos ^[1] ; Dias, Vanessa ^[3] ; Testoni, Giorgio ^[3] ; Rangel, Ricardo ^[1] ; Fraga, Mariana ^[4] ; Maciel, Homero ^{[3, 5]} ; dos Santos Filho, Sebastiao ^[1] ; Pessoa, Rodrigo ^{[3, 5]}

Affiliation

^[1] Univ Sao Paulo, Escola Politecn, Lab Sistemas Integraveis, BR-05508010 Sao Paulo - Brazil

^[2] Univ Aveiro, Dept Fis, I3N, Campus Univ Santiago, P-3810193 Aveiro - Portugal

^[3] ITA, LPP, BR-12228900 Sao Jose Dos Campos - Brazil

^[4] Univ Fed Sao Paulo, Inst Ciencia & Tecnol, BR-12231280 Sao Jose Dos Campos - Brazil

^[5] Univ Brasil, Inst Cient & Tecnol, BR-08230030 Sao Paulo - Brazil

• Document type: Journal article
• Source: NANOMATERIALS; v. 10, n. 2 FEB 2020.
• Web of Science Citations: 0

Abstract

In this paper, we report the plasma-enhanced atomic layer deposition (PEALD) of TiO2 and TiO2/Al2O3 nanolaminate films on p-Si(100) to fabricate metal-oxide-semiconductor (MOS) capacitors. In the PEALD process, we used titanium tetraisopropoxide (TTIP) as a titanium precursor, trimethyl aluminum (TMA) as an aluminum precursor and O-2 plasma as an oxidant, keeping the process temperature at 250 degrees C. The effects of PEALD process parameters, such as RF power, substrate exposure mode (direct or remote plasma exposure) and Al2O3 partial-monolayer insertion (generating a nanolaminate structure) on the physical and chemical properties of the TiO2 films were investigated by Rutherford backscattering spectroscopy (RBS), Raman spectroscopy, grazing incidence X-ray diffraction (GIXRD), and field emission scanning electron microscopy (FESEM) techniques. The MOS capacitor structures were fabricated by evaporation of Al gates through mechanical mask on PEALD TiO2 thin film, followed by evaporation of an Al layer on the back side of the Si substrate. The capacitors were characterized by current density-voltage (J-V), capacitance-voltage (C-V) and conductance-voltage (G-V) measurements. Our results indicate that RF power and exposure mode promoted significant modifications on the characteristics of the PEALD TiO2 films, while the insertion of Al2O3 partial monolayers allows the synthesis of TiO2/Al2O3 nanolaminate with well-spaced crystalline TiO2 grains in an amorphous structure. The electrical characterization of the MOS structures evidenced a significant leakage current in the accumulation region in the PEALD TiO2 films, which could be reduced by the addition of partial-monolayers of Al2O3 in the bulk of TiO2 films or by reducing RF power. (AU)

• FAPESP's process: 18/01265-1 - Synthesis and microbiological analysis of polymer substrates coated with TiO2 and / or Al2O3 ultra-thin films by atomic layer deposition technology
• Grantee: Rodrigo Savio Pessoa
• Support type: Regular Research Grants
• FAPESP's process: 15/05956-0 - 15th International Conference on Atomic Layer Deposition
• Grantee: Rodrigo Savio Pessoa
• Support type: Research Grants - Meeting - Abroad
• FAPESP's process: 11/50773-0 - Center of excellence in physics and applications of plasmas
• Grantee: Ricardo Magnus Osório Galvão
• Support type: Research Projects - Thematic Grants
• FAPESP's process: 15/10876-6 - Plasma-fungal biofilm interaction: diagnostic of the plasma and inactivation process of the Candida spp strains
• Grantee: Anelise Cristina Osorio Cesar Doria
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/17826-7 - Fabrication of MOS solar cells using structures Al/TiO2/SiO2/Si
• Grantee: William Chiappim Junior
• Support type: Scholarships in Brazil - Post-Doctorate