• PDF / 874,960 Bytes
• 5 Pages / 612 x 792 pts (letter) Page_size
• 56 Downloads / 168 Views

DOWNLOAD

REPORT

---

1066-A05-02

Polysilazane Precursor Used for Formation of Oxidized Insulator Yuji Urabe, and Toshiyuki Sameshima Tokyo University of Agriculture and Technology, 2-24-16, nakacho, koganei-shi, Japan ABSTRACT We report on SiO2 film formation using Polysilazane precursor treated with remote oxygen plasma and high-pressure H2O vapor heating. Polysilazane precursor films with a thickness of 130 nm were spin coated on silicon substrates. They were annealed at 350oC in remote oxygen plasma at a pressure of 2.0x10-2 Pa, frequency of 13.56 MHz and power of 300 W, and then followed by 13-atmospheric-pressure-water vapor heating at 260oC for 3 hrs. It was found that the films made by Polysilazane precursor were entirely oxidized by high-pressure H2O vapor thermal treatment, and the densities of Si-N and Si-H bonds inside those films diminished by the combination of double oxidized treatment. While Metal-Oxide-Semiconductor (MOS) capacitors fabricated only by high-pressure H2O vapor heat treatment had a high specific dielectric constant of 6.1, an oxide charge density of 1.3x1012 cm-2 and a density of interface trap of 5.4x1011 cm2 eV-1, the combination of oxygen-plasma-then-water-vapor-thermal oxidized treatment allowed us to reduce them to 4.1, 1.6x1011 cm-2 and 4.2x1010 cm-2eV-1, respectively, indicating better SiO2 dielectric material and SiO2/Si interface. INTRODUCTION The formation of good-quality SiO2 films and SiO2/Si interface at low temperature is important to fabricate high-quality and low-cost electronic devices, such as liquid crystal and organic electroluminescent displays. A low temperature process for SiO2 formation allow us to fabricate thin film transistors on inexpensive glass substrates and flexible substrates, as well reduce the production cost of solar cells. The SiO2 films from Polysilazane precursor, made by post-annealing process at 450oC in air, have been commercially applied for passivation films in LSI process. Moreover, the improvement in SiO2 films and SiO2/Si interface by high-pressure H2O vapor thermal treatment has been reported by us [1-8], which is ascribed to the better thermal relaxation inside a network of Si-O bonding. In this study, we report SiO2 film formation using Polysilazane precursor treated with remote oxygen plasma and high-pressure H2O vapor heating. The structural properties of Polysilazane and SiO2 films were characterized by Fourier transform infrared spectrometry (FTIR). The electrical properties of SiO2 films and SiO2/Si interface were characterized by Capacitance-Voltage (CV) measurement. It was demonstrated that the Polysilazane precursor were completely oxidized to SiO2 films with better electrical properties for gate dielectric material by our oxygen-plasma-then-water-vapor-thermal oxidized treatment. EXPERIMENT Polysilazane films with a thickness of 130 nm were spin coated on P-type single crystalline silicon substrates. 13.56 MHz radio frequency (RF) remote oxygen plasma treatment was carried out in O2 gas with a flow rate of 2 sccm at a pressure of 2.0x10-2 Pa, and a