Amorphous hydrogenated carbon films on semiconductors

Interface Properties of Hydrogenated Amorphous Carbon Films on Ge(100) Surfaces

“…A thorough knowledge of these properties is of paramount importance for the improvement of the adhesion quality. Our earlier study of a-C:H films on Si and GaAs substrates has shown that the adhesion is strongly promoted by chemical bonding and atomic interdiffusion (10,11). For both substrate materials we observed the formation of a carbidic compound at the interface resembling closely the phases SiC and AsC3, respectively, that can be found in the corresponding phase diagrams.…”

“…The sample with the disordered surface layer has the largest interface roughness. By comparing the results of Table I with our earlier findings for the Si substrate (11) we find that the method of substrate cleaning and the deposition parameters have a lesser effect on the properties of the a-C:H/Ge(100) interface than on the a-C:H/Si(100) interface. Nevertheless, the formation of a metastable compound and the atomic intermixing are still accountable for the adhesion quality of a-C:/H films on Ge substrates.…”

“…It is important to compare different cleaning methods since they are expected to influence the properties of the a-C:H/Ge(100) in- terface. Such was the case for the a-C:H/Si(100) and a-C:H/ GaAs(100) interfaces (11 ). The UPS valence band (VB) spectrum (hv = 21.2 eV) of the clean Ge(100) surface and a sequence of spectra measured after a number of deposition cycles are shown in Fig.…”

“…In the following we will show that the strong adhesion of a-C:H films on Ge material is not only due to atomic intermixing but also to the formation of a metastable compound.The paper is organized as follows: first we present a photoelectron spectroscopy investigation of the electronic structure of the a-C:H/Ge(100) interface, then we describe the atomic structure of the interface as observed with high resolution transmission electron microscopy and ion channeling. The analysis of the a-C:H/Ge(100) interface follows in spirit our earlier work on the a-C:H/Si(100) and a-C:H/ GaAs(100) interfaces (10,11).…”

Temperature dependence of silicon carbide interface formation: A photoelectron spectroscopy study

“…The deposition of amorphous hydrogenated carbon ͑a-C:H͒ requires the use of energetic ions, and the carbide formation has been reported in detail in several publications. [1][2][3][4] In contrast to the thermally activated process observed in our experiment, the additional energy input by the irradiation of the sample in the plasma-assisted deposition process for a-C:H leads to an increased thickness of the carbide interface. Schäfer et al 4 observed an interface thickness of 1.8 nm for a maximum ion energy of 200 eV, while Kawasaki et al 3 give values of 0.7 nm for ion energies around 350 eV and are unable to detect a carbide interlayer if ion energies as low as 15 eV are used.…”