Interdiffusion and compound formation in thin films of Pd or Pt on si single crystals

Abstract

The application of Pt or P d silicides in silicon device technologies stimulated interest in the crystallography and kinetics of compound formation between thin films of Pt or P d and bulk Si. Electron transmission observations of Pt-Si diffusion couples showed t h a t three compounds were formed during diffusion: Pt,Si, Pt,Si, and PtSi. The Pt,Si compound formed initially, followed by the formation of Pt,Si and PtSi. The Pt,Si compound disappeared as diffusion proceeded. The resulting film was found to be a two phase mixture of approximately 35 t o 40% Pt,Si and remainder PtSi. Long time annealing a t 650 "C resulted in no detectable changes from the two phase mixture. I n Pd-Si diffusion couples the dominant phase is Pd,Si with only small amounts of PdSi formed after vacuum annealing. In both cases it was concluded that the transformation to the PdSi or PtSi compound is determined by the kinetics of the transformation mechanism and not by the thermodynamic stability. F u r die Anwendung von Platin-oder Palladium-Siliziden in Silizium-Bauelementen ist die Untersuchung der Struktur und der Kinetik der Verbindungsbildung zwischen dunnen Schichten von Platin oder Palladium und dickem Silizium von Interesse. Mit Hilfe von Elektronenbeugung und Elektronenmikroskopie von Pt-Si-Proben konnte gezeigt werden, da13 drei Verbindungen, Pt,Si, Pt,Si und PtSi, wahrend des Diffusionsprozesses gebildet werden. Die Pt,Si-Phase wird im Anfangsstadium der Diffusionsprozesse gebildet, bei weiterem Tempern wird die Pt,Si-Phase abgebaut, wahrend die Pt,Si-und PtSi-Verbindungen auftreten. Die resultierende Schicht besteht aus ungefahr 35 bis 40% Pt,Si und 60 bis 65% PtSi. Langes nachtragliches Tempern bei 650 "C verursachte keine Anderung des Volumenverhaltnisses der zwei Phasen. I m Falle von Pd-Si-Proben wurde die Pd,Si-Verbindung als vorherrschende Phase gefunden. Die PdSi-Verbindung war nur in Spuren als Folge des Temperns im Vakuum vorhanden. Daraus kann geschlossen werden, daB in beiden Fiillen die Umwandlung in die PtSi-oder PdSi-Verbindung durch die Kinetik des Uqwandlungsmechanismus und nicht durch thermodynamische Stabilitat bestimmt ist.

Growth of silica nanowires in vacuum

“…When the reaction continued to proceed, it would completely transform into PtSi. 25,26 The compositional analysis by EDX (Table 1) confirms that the nanowires contain oxygen and silicon with a trace amount of platinum. The growth of nanowires in argon is determined by the well-defined VLS model, i.e., the formation of Si vapour is activated through disproportionation and phase separation of volatile SiO vapour.…”

Fluoride Ion Contamination and TiO Film Migration in the Ti‐Pt‐Au Metallization

“…Manuscript submitted May 23, 1975; revised manuscript received Aug. 4,1975. This was Paper 192 presented at the Toronto, Canada, Meeting of the Society, May 11-16, 1975.…”

“…Test structures with contacts shown in Fig. 1 and with known amounts of F-ion surface concentration were annealed in a vacuum (1)(2)(3)(4)(5) at temperatures up to 350~ in order to investigate gold migration, pinhole formation, and microcracking.…”

“…F-ions exist as probable sources of contamination from the contact etchant. In addition to contact contamination, a number of intermetallic compounds are formed in the diffusion couples of the Ti-Pt-Au system (4,5). These compounds include TisPt which has been postulated to be the high temperature diffusion barrier to gold-silicon interdiffusion (6).…”