Thermal stability of methyl groups on silicon(100) generated by the decomposition of tetramethylgermane

Abstract

The adsorption and thermal decomposition of tetramethylgermane on Si( 100) have been studied by ultraviolet photoelectron spectroscopy, static secondary ion mass spectrometry, temperature-programmed desorption, and Auger electron spectroscopy. Tetramethylgermane adsorbs molecularly on Si( 100) at 1 10 K. In temperature-programmed desorption experiments, most of the tetramethylgermane reversibly desorbs at 141 f 4 K. The remaining tetramethylgermane decomposes at higher surface temperatures by breaking of a C-Ge bond resulting in the formation of a methyl group and Ge(CH3)3, the latter evolving into the gas phase. Further heating causes decomposition of the methyl group. The hydrogen atoms released by methyl group decomposition form surface Si monohydrides, which later combine to desorb molecular H2 The methyl groups decompose with a pseudo-first-order preexponential of (1 f 5) X lo8 s-I and an activation energy of 29 f 1 kcal mol-].

Thermal chemistry of biacetyl on Si(100)

“…For example, Colainni et al 47 published HREELS results for CH 3 I on Si͑100͒ showing a substantial Si-H stretch around 2100 cm Ϫ1 after heating the surface to 700 K. Similarly, Greenlief and Klu, 22 and Kong et al 21 observed decomposition of ϪCH 3(a) forming surface hydrogen at 700 K. However, since the H 2 maximum desorption temperature occurs 70 K higher than reported for H (a) ϩH (a) recombination, the majority of the hydrogen transferring from C x H y O z species to the surface must not occur until 870 K. Annealing to the leading edge for H desorption at 700 K, we observe Si-H stretching at 2103 cm Ϫ1 in the HREELS, from which we conclude that C-H bonds break to form Si-H as low as 700 K, i.e., a surface-mediated dehydrogenation mechanism.…”

“…Ethylene reversibly adsorbs on Si͑100͒, whereas propylene and acetylene decompose, forming silicon carbide. [18][19][20][21][22] We recently studied acetone and acetaldehyde to ascertain the reactivity of carbonyls with silicon. However, methyl radicals, formed when methane is dissociated over a hot filament, readily adsorb and react to form SiC and diamond films.…”

Hydrogen desorption from Si: How does this relate to film growth?

“…33 The base pressure of the system is 6ϫ10 Ϫ11 Torr with a typical working pressure of 1ϫ10 Ϫ10 Torr. Si͑100͒ wafers ͑n-type, Sb doped, 10 m⍀-cm resistivity͒.…”

Atomically resolved scanning tunneling microscopy study of the adsorption and dissociation of methylchloride on Si(001)

“…Chlorine-on-silicon chemistry in particular has been extensively explored. 8 It was found that CH 3 groups are stable up to 600 K. At higher temperatures they react on the surface, releasing hydrogen and decomposing first into CH species and eventually into carbon. [1][2][3][4][5] Much less is known about the decomposition of organic species on silicon.…”