Auger electronic spectroscopy and electrical characterisation of InP(100) surfaces passivated by N2 plasma

International audienceAuger electron spectroscopy (AES) was used to investigate the processes taking place during the initial stages of InP(100) surfaces nitridation. This AES study combined with electrical measurements (intensity-potential) shows that the processes greatly differ depending on the nitridation angles. Results show that with grazing angle for nitrogen flow, the nitridation process is more efficient. Results obtained with AES spectra are coherent with electrical measurements : Hg/InN/InP(100) Schottky diodes present better electrical characteristics in the case of a grazing flow. That means, the adsorption of nitrogen on the surface is more important for this configuration

Elastično raspršenje elektrona od površine poroznog sloja silicija p-tipa

PSL samples have been formed on p type Si(100) wafers by an electrochemical procedure. The dependence of the elastic electron reflection coefficient, re(E), on porosity (P) was determined by elastic peak electron spectroscopy (EPES). The spectra were measured in absolute units (%) with a retarding field analyser and spectrometer corrections. They exhibited systematic decrease of intensity with porosity. HF treatment of samples produced a dramatic decrease of re(E) in the low energy (40-100 eV) range, due to removal of the native SiO2 and formation of Si-H bonds on the surface. It can be explained by multiple elastic reflection and attenuation of electrons by H adatoms on the pore walls. The constribution of pores to re(E) was considerable and increasing with porosity. The porous layers and interfaces have been studied by Auger electron spectroscopy (AES) with Ar+ ion bombardment depth profiling of high resolution.Uzorci slojeva p-silicija načinjeni su na Si(100) pločicama elektrokemijskim postupkom. Metodom elektronske spektroskopije za elastično raspršenje, određena je ovisnost elastičnog refleksijskom faktora, re, o poroznosti uzorka. Refleksijski faktor se smanjuje s povećanjem poroznosti. Jetkanje uzoraka s HF snažno je smanjilo r_e za niske energije elektrona (40 - 100 eV) zbog uklanjanja SiO2 i stvaranja Si–H vezanja na površini. Porozni slojevi i granice proučavani su Augerovom elektronskom spektroskopijom, primjenom snopa Ar+ i dubinskog odredivanja profila uz visoko razlučivanje

First stages of the InP(1 0 0) surfaces nitridation studied by AES, EELS and EPES

The nitrides of group III metals: AlN, GaN and InN are very important materials due to their applications for short wavelength opto-electronics (light-emitting diodes and laser diodes). It is essential for the realization of such novel devices to grow high-quality nitride single crystals. In this paper, we report the first stages of the InP(1 0 0) surfaces nitridation in order to grow high-quality nitride films. Indeed, the nitridation process is an important step in the growth of nitrides [J. Vac. Sci. Technol. A 17 (1999) 2194; Phys. Status Solidi A 176 (1999) 595]. Previous works [Synth. Met. 90 (1997) 2233; Appl. Phys. Lett. 63 (1993) 1957] have shown that in situ Ar+ ions bombardment is useful on the one hand to clean the surface, and on the other hand to create droplets of metallic indium in well-controlled quantity. Then the indium metallic enrichment of the surface, monitoring by elastic peak electron spectroscopy (EPES) and Auger electron spectroscopy (AES) allows to prepare the III-V semiconductors surfaces to the nitridation step. The nitridated process has been performed with a high voltage plasma discharge cell and has been studied using quantitative Auger electron spectroscopy, elastic peak electron spectroscopy and electron energy loss spectroscopy (EELS), in order to optimize the conditions of InN layers formation

Nitridation of InP(1 0 0) surface studied by synchrotron radiation

The nitridation of InP(1 0 0) surfaces has been studied using synchrotron radiation photoemission. The samples were chemically cleaned and then ion bombarded, which cleaned the surface and also induced the formation of metallic indium droplets. The nitridation with a Glow Discharge Cell (GDS) produced indium nitride by reaction with these indium clusters. We used the In 4d and P 2p core levels to monitor the chemical state of the surface and the coverage of the species present. We observed the creation of In-N and P-N bonds while the In-In metallic bonds decrease which confirm the reaction between indium clusters and nitrogen species. A theoretical model based on stacked layers allows us to assert that almost two monolayers of indium nitride are produced. The effect of annealing on the nitridated layers at 450 $^\circ$C has also been analysed. It appears that this system is stable up to this temperature, well above the congruent evaporation temperature (370 $^\circ$C) of clean InP(1 0 0): no increase of metallic indium bonds due to decomposition of the substrate is detected as shown in previous works [L. Bideux, Y. Ould-Metidji, B. Gruzza, V. Matolin, Surf. Interface Anal. 34 (2002) 712] studying the InP(1 0 0) surfaces