The effect of a small amount of Pt (5 at. %) on the thermal stability of NiSi film on (100) and (111) Si substrates has been investigated both by in situ annealing inside an x-ray photoelectron spectroscopy system and by ex situ rapid thermal annealing. The addition of platinum increases the disilicide nucleation temperature to 900 °C leading to a better stability of NiSi at high temperatures. In the presence of Pt, NiSi films on both (111)Si and (100)Si substrates develop a texture with the relationship (100)NiSi∥(111)Si and (010)NiSi∥(100)Si. The increase in thermal stability has been explained in terms of the nucleation concept.

In an effort to elucidate the mechanism of scallop formation during reflow of solder/Cu joints in flip-chip and ball-grid array technologies, a planar intermetallic compound layer (mostly Cu6Sn5) was initially formed by solid-state annealing of SnPb/Cu joints at 150 °C for ten days. Upon subsequent reflow, dissolution of the intermetallics and formation of scallops were observed. Detailed investigation has indicated that a thermal grooving process due to dissolution of the intermetallic compound during the initial reflow cycles contributes to the formation of scalloped structures, the morphology of which is dictated by the force equilibrium condition. Upon subjecting the solder joints to several reflows, the average intermetallic layer thickness was found to first decrease and then increase, which is shown to be in good agreement with the prediction made by a model based on simultaneous dissolution and growth of the intermetallic compound during reflow. The kinetics of dissolution-growth process during reflow has also been shown to depend on the initial intermetallic thickness and the shape of the solder cap.

The roughness evolution of the Cu6Sn5 intermetallic compound during the soldering reaction of 40/60% (by wt %) PbSn solder on Cu and its effects on wettability were studied due to their importance in the reworking of microelectronic components. The roughness parameters investigated were Rrms and the ratio, Rrms/λa, where Rrms is the root mean square roughness and λa is the average distance between asperities. It was found that Rrms increased with soldering time for the range of soldering times studied. The evolution of Rrms was found to follow a parabolic relation with soldering time—which is similar to that observed for the intermetallic thickness. However, the ratio Rrms/λa was found to increase very gradually for the range of soldering times investigated. From the ratio Rrms/λa obtained, the average inclination of the intermetallic morphology was calculated. The average inclination of the Cu6Sn5 intermetallic morphology was found to be greater than the apparent contact angle observed during the wetting of the 40/60% PbSn solder on Cu substrates. This inconsistency was attributed to the difference in the roughness of the Cu6Sn5 intermetallic in the inner regions and at the reaction band at the edge of the solder cap.

Growth of high performance InGaAs/InP doped channel heterojunction field effect transistor with a strained GaInP Schottky barrier enhancement layer by gas source molecular beam epitaxy Sub-40 nm PtSi Schottky source/drain metal-oxide-semiconductor field-effect transistors

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