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Title: Characterisation of zinc and beryllium doped indium phosphide grown by molecular beam epitaxy
Author: Park, Robert McIlwraith
ISNI:       0000 0001 3468 2431
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1981
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The purpose of the work reported in this thesis was two-fold. The first objective was to investigate the incorporation behaviour of both zinc (Zn) and beryllium (Be) in molecular beam epitaxy (MBE) grown indium phosphide (InP) with a view to growing device quality p-type InP material. Secondly, a deep level transient spectroscopy (DLTS) system was designed and constructed in order to detect and possibly identify deep level majority carrier trapping centres in MBE grown InP, the aim behind this investigation being to provide feedback information in order to improve the quality of InP grown by MBE. Prior to commencing the doping study an investigation was carried out into the growth of unintentionally doped InP by MBE onto Fe-doped semi-insulating InP substrates which were atomically cleaned in-vacuo by the process of argon ion sputtering followed by annealing. Hall-effect and plasma reflectivity measurements made on unintentionally doped InP films grown onto sputtered and annealed substrates yielded substantially different results; Hall-effect measurements typically yielded nett donor concentrations N[D]-N[A] of ~3x10-1cm-1 and electron mobilities < 1000 cm2V-1s-1 at R.T. while higher electron mobilities, typical = 3,000 cm2V-1s-1, were obtained by the plasma reflectance technique with N[D]-N[A] being = 10-1cm-3. This result lead to speculation that the substrate/film interface region was seriously influencing electrical measurements on the films and an investigation into the effects of the sputtering and annealing cleaning process on substrate surfaces was initiated to verify this hypothesis. Hall-effect and C-V profiling techniques revealed that the surface of semi-insulating substrates is converted to n-type with N[D]-N[A] in the range 1016-1017cm-3 to a depth of ~ 1,000A as a result of the sputtering and annealing process. Hence films grown onto sputtered and annealed substrates are interfaced by a conducting layer. Zn was found to have a near unity sticking coefficient on (100) InP grown by MBE at substrate temperatures around 360°C and Zn concentrations up to ~4x10²⁰cm⁻³ were achieved in films as measured by atomic absorption spectrometry analysis with no apparent degradation of either the surface morphology or crystal structure.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Chemistry, general