Transmission electron microscopy characterization of the erbium silicide formation process using a Pt/Er stack on a silicon-on-insulator substrate

Very thin erbium silicide layers have been used as source and drain contacts to n-type Si in low Schottky barrier MOSFETs on silicon-on-insulator substrates. Erbium silicide is formed by a solid-state reaction between the metal and silicon during annealing. The influence of annealing temperature (450 degrees C, 525 degrees C and 600 degrees C) on the formation of an erbium silicide layer in the Pt/Er/Si/SiO2/Si structure was analysed by means of cross-sectional transmission electron microscopy. The Si grains/interlayer formed at the interface and the presence of Si grains within the Er-related layer constitute proof that Si reacts with Er in the presence of a Pt top layer in the temperature range 450-600 degrees C. The process of silicide formation in the Pt/Er/Si structure differs from that in the Er/Si structure. At 600 degrees C, the Pt top layer vanishes and a (Pt-Er)Si-x system is formed

Formation of Pt-based silicide contacts : kinetics, stochiometry and current drive capabilities

A detailed analysis of the formation of Pt2Si and PtSi silicides is proposed, based on x-rayphotoelectron spectroscopy ~XPS!, transmission electron microscopy ~TEM!, and electricalcharacterizations. Published kinetics of the Pt2Si and PtSi transformations under ultrahigh vacuumcondition are consolidated on the basis of XPS measurements performed during an in situ annealingat a constant heating rate. At room temperature, an incomplete PtxSi reaction is clearly identified byXPS depth profiling. Using rapid thermal annealing at 300, 400, and 500 °C, the sequentialPt–Pt2Si–PtSi reaction chain is found to be completed within 2 min. Outdiffusion of silicon to thetop surface is shown to be responsible for the formation of a thin SiO2 capping layer at 500 °C.Pileup of oxygen occurring at the Pt2Si/Pt reaction front is clearly identified as an inhibiting factorof the silicidation mechanism. Another incomplete reaction scheme limited to the unique formationof Pt2Si is exemplified in the case of ultra thin silicon-on-insulator films. Finally, current drivemeasurements on PtSi Schottky contacts have allowed us to identify 300 °C as the optimumannealing temperature while TEM cross sections demonstrate the formation of a smooth andcontinuous PtSi/Si interface at 300 °C

Electron microscopy study of advanced heterostructures for optoelectronics

The application of cross-sectional transmission electron microscopy and SEM to the investigation of optoelectronic devices are reviewed. Special attention was paid to the electron microscopy assessment of the growth perfection of such crucial elements of the devices like quantum wells, quantum dots, distributed Bragg reflectors as well as elec. contacts. Using these examples, the most important issues of the application of electron microscopy to characterization of optoelectronic devices are discussed. [on SciFinder (R)