José Alexandre Diniz
Unicamp – Brazil
Thursday, Aug. 30 – 13:40h – Malbec A
Jose Alexandre Diniz
SBMicro INVITED TALK:
Ultra-Thin and Thin Films for Nano and Micron Technologies
This work presents the formation and characterization of different films (Pt, TiN, TaN, TiAlO, TiAlON, SiNx, SiO2 and SiON), which were obtained using different vacuum systems, such as: Sputtering, Electron Cyclotron Resonance (ECR)-Chemical Vapor Depositon (CVD), Electron Beam Evaporator (EBE), Focused Ion Beam (FIB) and Electron Beam Lithography (EBL). These films can be ultra-thin and thin, with thickness values, respectively, between 1.5 nm and 20 nm, and thicker than 20 nm up to 300 nm. Furthermore, these films are used to obtain electronic devices based on MOS (Metal-Oxide-Semiconductor), HBT (Heterojunction Bipolar Transistor) and Graphene technologies, with nano and micron dimensions. It is important to notice that, these technologies and facilities are developed and installed, respectively, at University of Campinas in Brazil.
Today, the MOS transistors, which are used in actual high performance integrated circuit, have three crystalline planes of conduction channel into the silicon nano wires (SiNW) and are named 3D MOS transistors. In this work, to define the SiNWs, FIB milling of Si substrate is used. Thus, we can fabricate two kinds of 3D MOS transistors, JunctionLess (JL) and FinFETs (Fin Field Effect Transistors). The metals, which are used in these devices for drain, source and gate electrodes, are Pt (100 nm), deposited by FIB, TiN (20 nm) and Al (100 nm), deposited by sputtering. The gate dielectrics are the traditional SiO2, obtained by FIB deposition and thermal oxidation of Si, and high-k insulators, such as SiON (3 nm), obtained by plasma oxynitrdation in ECR system, and TiAlON (8nm), obtained by Ti (0.7nm)/Al (0.3nm) deposition using EBE with additional plasma oxynitridation in ECR system.
HBT devices are used for high frequency (> 10 GHz) applications. To get the high performance for these frequencies, the surface passivation, mainly, between emitter and base regions, allows the leakage current reduction, which results the current gain. Our HBTs are based on III-V semiconductors (InGaP/GaAs) and the passivation layer (60nm) is SiNx, obtained by ECR-CVD.
The FET devices with Graphene conduction channel (GraFETs) are fabricated using Graphenes obtained by CVD and TiN (100 nm) or TaN (100 nm) electrodes for source and drain contacts, deposited by Sputtering.
The structural characteristics of all films are extracted from EDS (X-Ray Energy Dispersive Spectroscopy), for the composition, SEM (Scaning Electron Microscopy) and OM (Optical Microscopy), for surface analysis, Raman Spectroscopy, for crystallinity structure, Ellipsometry, for thickness and refractive index. The electrical characteristics of all devices are extracted from Current versus Voltage (I-V) curves.
Other Colaborators of this Work:
L.P.B.Lima, A. Leonhardt, C.V. Carnio, A. M. Rosa, C.R. Almeida, A. M. Pascon, A. R. Silva, F. H. Cioldin, L.B. Zoccal, I. Doi and L. T. Manera