The synthesis and characterization of novel precursors for the CVD of main group metal phosphides

• Main Author: Apostolico, Leonardo
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2003
• Subjects: Materials science
• ISBN: 1303575000; 9781303575006

The syntheses and characterizations of germanium and tin compounds as novel single-source precursors for the deposition and growth of thin films of metal phosphides have been investigated and described in this thesis. 1:1 reactions of germanium(IV) chloride with primary and secondary phosphines have been studied and formation of crystalline salts, i.e. [GeCb]- [CyPHa]+ and [GeCl3nPh2pH2]+, have been observed. Employment of a large excess of GeCI4, instead, facilitates the complete consumption of phosphine and promote the synthesis of chlorogermyl phosphines Cl3GeP(R)H which have been investigated and fully characterized. Their suitability as precursors for the CVD of thin films of germanium phosphide is also reported. The successful syntheses and characterization of organogermyl phosphides from organogermyl chloride (R4-nGeCln with n = 1, 2 and R = Ph, Et) and Me3SiPPh2 are reported. Decomposition of the materials to germanium phosphide films has been ascertained. Reactions of tin(IV) halides with primary, secondary and tertiary phosphines are reported. Formation of crystalline salts deriving from redox processes have been ascertained and X-ray diffraction structures have been studied, [Snl4}2[CyPH3]2+. [Sn3I12]6[Ph2PH2]6+ [SnI6]2- [Ph2PH2]2+ [Snl3]-[Cy3PI]+ [Snl5]-[Cy3PI]+, [SnCl5-THF]-[Cy3PH]+. In only one case, reaction of SnCI4 with Cy3P has the formation of an adduct, SnCI4 PCy3, been noted and which has been fully characterized and employed as single-source precursor for the deposition of SnP films. Finally, preparation of Ph3SnPPh2 via different routes is described. Ph3SnPPh2 has been fully characterized and used as precursor for the CVD of tin phosphide. Synthesis of 'Bu3SnPPh2 has been attempted but failed to deliver a pure product that could not be isolated. All the films produced have been studied by scanning electron microscopy and energy dispersive X-ray analysis.