Growth of Ge Homoepitaxial Films by Metal-Organic Chemical Vapor Deposition Using t-C₄H₉GeH₃

Abstract

Ge homoepitaxial films are grown at low growth temperature of 320 • C by metal-organic chemical vapor deposition (MOCVD) using tertiarybutylgermane (t-C 4 H 9 GeH 3 ). We also performed ab initio calculations in order to reveal the chemical reaction for the epitaxial growth. As the result, it was revealed that the t-C 4 H 9 GeH 3 was most likely decomposed into germane (GeH 4 ) and isobutene [CH 2 =C(CH 3 ) 2 ] through the β-hydrogen elimination. We considered that this chemical nature allowed the growth temperature as low as that obtained by GeH 4 precursor with sufficiently suppressed C impurity incorporation.

Atmospheric pressure metal organic chemical vapor deposition of thin germanium films

“…14). This value is significantly lower as reported for other organogermanium(IV) precursors (GeEt 4 142 kJ/mol [73], GeH 3 tBu 160 kJ/mol [45], and GeVinyl 4 185 kJ/mol [46]). The digermane Ge 2 H 6 also shows a higher activation energy of 125 kJ/mol at 0.0039 mbar and 163 kJ/mol at 0.295 mbar [74].…”

“…With the development of new germanium-based functional materials for energy conversion [1], for lithium-ion batteries [2][3][4][5][6][7][8][9][10][11] or as photocatalysts [12], the synthesis of germanium nanorods, [13] nanowires [14][15][16][17][18][19], and nanoparticles [20][21][22][23][24][25][26] has significantly gained in importance. In addition, germanium thinfilms are of great interest with regard to potential applications, e.g., photovoltaics [27], plasmonics [28], optoelectronics [29], electronics [30][31][32], optics Therefore, diverse methods for the fabrication of germanium films such as thin-film transfer [38], AFM nanolithography [39], or laser photolysis techniques [40,41] were reported, and in most cases, the deposition of films is addressed via the gas phase, e.g., atomic layer deposition (ALD) [42], physical vapor deposition (PVD) [31,43,44], or metal organic chemical vapor deposition (MOCVD) [45][46][47]…”

“…By introducing an organic ligand at germanium, the sensitivity to oxygen and water, the decomposition temperature, the solubility, and the volatility of the precursors can be controlled, which greatly improves their handling compared to inorganic precursors, especially with regard to those that are gaseous such as GeH 4 . Thus, organogermanes such as GeH 3 tBu [45], GeVinyl 4 [46], GeH 3 Blz [47], and GeH 3 Cp* [48] (tBu = C(CH 3 ) 3 ; Vinyl = CHCH 2 ; Blz = CH 2 C 6 H 5 ; Cp* = C 5 Me 5 ) were demonstrated to be suitable for the deposition of germanium films. In particular, GeH 3 Cp* and GeH 3 Cp 4M (Cp 4M = C 5 Me 4 H) show a high potential due to their volatility and low decomposition temperature with regard to the production of germanium films, but so far they were accessible with rather low yield only [47,48].…”

Biaxial stress evaluation in GeSn film epitaxially grown on Ge substrate by oil-immersion Raman spectroscopy

“…The strained Ge 1−x Sn x films were epitaxially grown on the (001) Ge substrate by metal-organic chemical vapor deposition (MOCVD) using tertiary butyl germane (t-C 4 H 9 GeH) and tetraethyltin [(C 2 H 5 ) 4 Sn] as Ge and Sn precursors, respectively. [26][27][28][29] Sn concentrations were 1.8, 2.2, and 3.2%, which were determined by Rutherford backscattering spectrometry (RBS). From RBS measurements, Sn segregation was not observed on the outermost surface of Ge 1−x Sn x films, with uniform Sn concentration.…”

Selective growth of Ge1−xSnxepitaxial layer on patterned SiO2/Si substrate by metal–organic chemical vapor deposition

“…Recently, the epitaxial growth of Ge and Ge 1−x Sn x layers with metal-organic (MO) precursors has been reported. [22][23][24][25][26][27][28][29][30][31][32] MO precursors can be generally easily handled because they are safer than hydrogen precursors, and they also hardly cause corrosion of metals unlike chlorine precursors.…”