Physics |
|
 |
2004, No. 4
V.A. Rozhkov, A.I. Rodionov, M.B. Shalimova, A.V. Pashin, A.M. Guryanov
ANTIREFLECTION AND PASSIVATING COATINGS ON THE BASIS OFRARE EARTH ELEMENT OXIDES FOR SILICON DEVICES
In this research the optical properties of Rare Earth Elements'(REE) Oxide films, the antireflection effect on silicon surfaces and photoelectric transducers covered by these films, and the recombination properties of silicon, passivated by REE oxide films are studied. The investigations show that the deposition of a REE oxide film onto silicon surface decreases the spectral light reflection index from the surface of silicon down to 0.01-1.2%, increasing the spectral value of short-circuit photocurrent in a silicon photoelectric transducer more than by 50%. It is found out that after a deposition of a rare earth element oxide film the effective life-time of the non-equilibrium charge carriers, measured by means of photoconductivity relaxation method, increases 2-3 times. The surface recombination rate values for the interface silicon-rare earth element oxide are determined. For different REE oxides they are equal to
V.A. Rozhkov, M.A. Rodionov, A.V. Pashin, A.M. Guryanov
GADOLINIUM OXIDE. NEW DIELECTRIC STRUCTURES FOR ULSI CIRCUITS
A new dielectric structure which consists of a thin thermally oxidized gadolinium on silicon with and without a thin intermediate SiO2 layer is investigated as a high storage capacity insulator for ultra-large-scale integrated (ULSI) circuits. In the paper electrical characteristics of Al/gadolinium oxide (25 nm)/Si structures are described. The Al/Gd2O3/SiO2/Si (MGOS) and Al/Gd2O3/Si (MGS) capacitors show very well-behaved volt-amps characteristics with leakage current density 10-10 A·cm-2 at 5 V. High-frequency voltage-capacitance characteristics show without hysteresis for bias ramp rate ranging 2 V·s-1. The average interface charge density ( Qf + Qit ) is 2,8·10-7 C·cm-2 and interface state density Nss is 7,8·1011 cm-2·eV-1 near the flat band potential of silicon. These electrical characteristics and dielectric constant of 11-12 for gadolinium oxide on Si make it a viable dielectric for dynamical random access memory (DRAM) storage capacitors and for decoupling capacitors for on- and off-chip applications.