Formation of epitaxial yttrium silicide on (111) silicon

Abstract

The growth of epitaxial yttrium silicide on Si(111) in ultrahigh vacuum is studied. Resistivity, epitaxial quality, and pinhole coverages are studied as a function of annealing temperature for each growth method used. The best films result from the growth of a thin, 30–40-Å template layer which is annealed to 700 °C, followed by a thicker film growth by depositing additional Y onto the substrate heated high enough to induce silicide formation (∼300 °C). Annealing to 900 °C results in a Rutherford backscattering minimum channeling yield χmin ∼3%, which is the same order of epitaxial quality previously achieved by only Ni- and Co-silicide films on silicon. Films grown without templates have larger pinhole sizes with pronounced features indicative of the hexagonal nature of these structures. The deposition of Y metal onto a substrate held at room temperature, followed by annealing to 900 °C results in the lowest resistivities (48 μΩ cm for 425-Å films), but with a highly dislocated film structure featuring 1-μm triangular pits which severely limit epitaxial quality.

Ultra compact multitip scanning tunneling microscope with a diameter of 50 mm

“…This value can be compared to a resistivity of about 50 μ cm measured on thin yttrium silicide thin films. 18,19 This value is also comparable to the resistivity measured before on cobalt silicide nanowires using multitip scanning tunneling microscopes.…”

Growth of pinhole-free epitaxial Yb and Er silicide thin films on atomically clean (111)Si

“…Extensive studies on the formation of pinholes have been carried out. [13][14][15][16] Many methods to overcome this problem, and mechanisms for pinhole formation, have been reported. The formation of pinhole-free RESi 2-x thin films on ͑111͒Si has been reported by Kaatz et al 14 and Siegal et al 15 The method proposed by Kaatz et al is to codeposit the metal and silicon species at room temperature followed by an anneal at high temperature.…”

“…[12][13][14][15][16][17][18] The formation of pinholes in epitaxial RE silicides is a serious problem. The presence of pinholes may result in short circuits or direct contact of upper layers to Si substrate, and thus decrease the device reliability.…”

Planar defects and double-domain epitaxy in epitaxial YSi2−x and ErSi2−x thin films on Si substrates

“…[1][2][3] In addition, the excellent lattice match between the RE silicides of hexagonal AlB 2 structure and Si substrates offers an opportunity to grow high-quality epitaxial silicides on silicon. [4][5][6][7] Recently, RESi 2-x nanowires were grown on (001)Si. [8][9][10][11] Because the physical properties of nanowires are expected to be dependent on the defect structures, it is of great interest to investigate the defect structures in both RESi 2-x nanowires and epitaxial thin films.…”