In situ study of Ge(100) surfaces with tertiarybutylphosphine supply in vapor phase epitaxy ambient

Abstract

GalnP nucleation on Ge(100) often starts by annealing of the Ge(100) substrates under supply of phosphorus precursors. However, the influence on the Ge surface is not well understood. Here, we studied vicinal Ge(100) surfaces annealed under tertiarybutylphosphine (TBP) supply in MOVPE by in situ reflection anisotropy spectroscopy (RAS), X-ray photoelectron spectroscopy (XPS), and low energy electron diffraction (LEED). While XPS reveals a P termination and the presence of carbon on the Ge surface, LEED patterns indicate a disordered surface probably due to by-products of the TBP pyrolysis. However, the TBP annealed Ge(100) surface exhibits a characteristic RA spectrum, which is related to the P termination. RAS allows us to in situ control phosphorus desorption dependent on temperature.

Development of the Lattice Matched GaInP/GaInAs/Ge Triple Junction Solar Cell with an Efficiency Over 40%

“…First, since Ge presents a non-polar structure, a heteroepitaxial routine is required to grow defectfree polar III-V layers on a Ge substrate. This can be accomplished by the use of a misoriented Ge substrate [7], together with a dedicated surface preparation prior to growth [8][9][10][11]. For this particular case, RAS has been used as an insitu characterization technique in order to have a careful control of the growing surface.…”

Impact of the III-V/Ge nucleation routine on the performance of high efficiency multijunction solar cells

“…Some of the aforementioned problems or trade-offs have been studied by different research groups over the last two decades [8][9][10]. For example, the use of misoriented substrates [11] in conjunction with specific surface preparation routines [12][13][14][15] have been widely employed to grow defect-free III-V nucleation layers on Ge substrates. Another example of surface preparation, in this case for the growth of GaAs on Ge by MBE for laser diode applications, was the use of a Ga pre-layer technique that favors smoother surface morphology [16].…”

Effect of Ge autodoping during III-V MOVPE growth on Ge substrates

“…First, since Ge presents a non-polar structure, a heteroepitaxial routine is required to grow defect-free polar III-V layers on the Ge substrate. This can be accomplished by the use of a misoriented Ge substrate [2], together with a dedicated surface preparation prior growth [3,4,5,6].…”

“…Similar SIMS profiles have been shown in[22,17] when growing Ga(In)As or GaInP on Ge substrates at 650ºC and 630ºC, respectively. The right part ofFigure 3shows a zoomin of the profiles associated to Ge autodoping for GaInP and Ga(In)As grown at 675ºC, namely, region(3). For the case of reactor pre-condition #C (black line) where a thicker and more complex coating…”