Thermal Stability of GdScO 3 Dielectric Films Grown on Si and InAlN/GaN Substrates
- PDF / 477,213 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 53 Downloads / 180 Views
1155-C09-03
Thermal stability of GdScO3 dielectric films grown on Si and InAlN/GaN substrates
K. Fröhlich1, A. Vincze2, 3, E. Dobročka1, K. Hušeková1, K. Čičo1, F. Uherek2, 3, R. Lupták1, M. Ťapajna1, D. Machajdík1 1 Institute of Electrical Engineering, SAS, Dúbravská 9, 841 04 Bratislava, Slovak Republic 2 International Laser Center, Ilkovičova 3, 841 04 Bratislava, Slovak Republic 3 Department of Microelectronics, FEI STU, 812 19 Bratislava, Slovak Republic
ABSTRACT We present analysis of thermal stability of thin GdScO3 films grown on silicon and InAlN/GaN substrates. The GdScO3 films were prepared by liquid injection metal organic chemical vapor deposition at 600 °C. The films were processed after deposition by rapid thermal annealing in nitrogen ambient at 900, 1000 and 1100 °C during 10 s. In addition, annealing of the GdScO3 films on InAlN/GaN substrate at 700 °C during 3 hours was performed. The samples were analyzed by grazing incidence X-ray diffraction (GIXRD), X-ray reflectivity (XRR) and time-of-flight secondary ion mass spectroscopy (ToF SIMS). GIXRD confirmed that the as-deposited GdScO3 films were amorphous. Recrystallization of the films on both substrates occurred at 1100 °C. ToF SIMS depth profile of the films annealed at 1000 °C indicated strong reaction of the GdScO3 film with the Si substrate. For the InAlN/GaN substrate rapid thermal annealing at 900 °C induced diffusion of the In and Al atoms into the top GdScO3 layer. Thermal treatment at 700 °C for 3 hours presents upper limit of the acceptable thermal budget for the GdScO3/InAlN interface.
INTRODUCTION Gadolinium scandate is considered as an alternative gate dielectric material in CMOS technology due to its κ value higher than 20. Up to now thin films of rare earth scandates films were prepared using pulsed laser deposition [1], electron beam evaporation [2], atomic layer deposition [3, 4], and metal organic chemical vapor deposition [5]. Alternatively, GdScO3 can be used as the gate insulation in high power – high frequency high electron mobility GaN based transistors (HEMT). Integration of GaN based HEMT’s with CMOS technology is a challenging objective, as it would allow new electronic applications. However, thermal stability of the dielectric film is a key property for both applications. It was already concluded, that the advantage of the rare earth scandates thin films over other high-κ materials is, that they preserve their amorphous structure at temperatures up to 1000 °C. However, more detailed studies have revealed limited thermal stability of dysprosium scandate on Si substrate [5, 6]. It has been observed, that dysprosium scandate thin films form
silicate under high temperature anneal. More experimental data is required to understand rare earth scandates thin film behavior at elevated temperatures. In our contribution we analyze properties of thin GdScO3 films on two different substrates (Si and InAlN/GaN) submitted to high temperature post-deposition processing. EXPERIMENT The GdScO3 films were deposited at 600 oC using G
Data Loading...
