Untersuchung des selbstorganisierenden Wachstums von Ge-C-Si/Si-Strukturen im Hinblick auf nulldimensionale Effekte

In this work the morphological, optical and electronic properties of nominally pure germanium islands grown on Si(001) substrates are investigated, both with and without a carbon predeposition layer. Low pressure chemical vapour deposition (LPCVD) is used for epitaxy of the Si, Ge and C layers. When depositing Ge at 700 C, two different types of islands are observed: small pyramidal-shaped islands with shallow facets and large islands with steep facets and a rounded shape. Photoluminescence measurements indicate that the large, round-shaped dots exhibit a high radiative recombination efficiency. Calibration measurements of carbon incorporation into a Si_0_._8_8Ge_0_._1_2 layer using propane as carbon precursor at a deposition temperature of 700 C show that up to 0.09% of substitutional carbon can be found in the layers. The modification of Ge island growth is investigated by depositing a carbon layer of 0.01-0.03 ML thickness at 700 C prior to the Ge islands. At a Ge growth temperature of 600 C a homogeneous distribution of small-sized islands (lateral sizes between 8 nm and 25 nm) are observed. Thus we can show that a modification of Ge island growth by a carbon predeposition layer can be achieved using PLCVD. Finally, the possibility of using GE islands in electronic devices, i.e. Esaki tunnelling diodes, is investigated. By depositing Ge on Si mesas, prepared previously by selective epitaxy, islands preferably nucleate on shallow #left brace#1 0 12#right brace# facets, thus offering a mechanism to control the islands' position. (orig.)SIGLEAvailable from TIB Hannover: RA 831(3844) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman