Electrical properties of AlN thin films deposited at low temperature on Si(100)

Aluminum nitride (AlN) films have been grown on Si(100) using sequential dosing of ammonia and dimethylethylamine alane (DMEAA). Growth rates were larger than that expected for atomic layer growth (ALG), and characterization of the films shows the duration of the DMEAA dose can be used to control the growth rate. X-ray diffraction measurements indicate that the AlN crystal structure undergoes a transition from amorphous to polycrystalline at a growth temperature of similar to 550 K. Spectroscopic ellipsometry shows that a 2 s versus 4 s DMEAA step in the growth sequence yields an AlN film with refractive index more representative of AlN films reported previously. Films were made into metal-insulator-semiconductor (MIS) de vices by evaporating aluminum in a dot array on the him surface. Capacitance-voltage (C-V) traces on the MIS devices indicate the films had a dielectric constant of 6.1-7.0 which is less than other published values for aluminum nitride. Hysteresis in the C-V traces indicates a significant number of charge traps in the films. The electric field required for irreversible dielectric breakdown was similar to 2-3 MV/cm, and the charge leakage characteristics showed a semilog trend with growth temperature. (C) 1999 Elsevier Science S.A. All rights reserved.