Structural and Defect Study of Low Temperature INP Grown by Gas Source Molecular Beam Epitaxy
- PDF / 294,250 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 12 Downloads / 208 Views
STRUCTURAL AND DEFECT STUDY OF LOW TEMPERATURE INP GROWN BY GAS SOURCE MOLECULAR BEAM EPITAXY J.Ch.Garcia, J.P.Hirtz, P.Maurel, H.J. Von Bardeleben*, J.C.Bourgoin* THOMSON CSF Laboratoire Central de Recherches, Domaine de corbeville 91404 Orsay FRANCE * Groupe de Physique des Solides de I' Universit6 Paris VII, 2 place Jussieu 75221 Paris FRANCE ABSTRACT The low temperature growth procedure used in the case of GaAs to introduce high concentrations of deep traps such as arsenic antisite defects has been extended to the growth of InP by gas source molecular beam epitaxy. The low temperature growth of InP induces a strong group V stoechiometric deviation (of the order of +1%). On the other hand, Secondary Ion Mass Spectrometry reveals high levels of hydrogen ranging from 3.1018 to 3.1019 cm- 3 depending on growth temperature. Undoped layers are found to be resistive without any post annealing. Annealing experiments above 250 0 C lead to conductive layers suggesting a passivation effect of both shallow donors and acceptors by hydrogen. INTRODUCTION The route to produce semi-insulating (SI) III-V materials is based on the introduction of a concentration of deep traps larger than the residual shallow impurity concentration. That can be obtained by a low temperature growth process. GaAs epitaxial layers grown by Molecular Beam Epitaxy (MBE) at low temperature (200°C-3000 C) have shown interesting SI properties [1,2]. The deep traps have been correlated with the strong As-rich stoechiometry (up to 1%) and identified as arsenic antisite defects [3]. This type of material has been used as buffer layers to reduce backgating, sidegating and ligth sensitivity effects in MESFET [4, 5]. This low temperature growth approach used successfully for GaAs can be extended to other arsenide compounds such as AIGaAs [6], AlInAs [7]. Concerning InP, the growth of SI layers is usually obtained by iron doping. However, the Fe dopant gives rise to various problems such as low thermal stability, electrical activity which decreases sharply on vicinal (100) and high index planes (111) and
Mat. Res. Soc. Symp. Proc. Vol. 241. @1992 Materials Research Society
278
finally dopant interactions when co-doped with Zn [8]. Anionic antisite (Pin) could also, in principle, play a decisive role in the production of SI layers by Fermi level pinning since, by analogy with the ASGa, the phosphorus antisite is a double donor with a first ionisation level 04+ located near midgap. However, it appears difficult to grow InP at low temperature by the MOVPE technique because the growth is limited to 300-350 0 C by the surface decomposition of both metalorganic and hydrides molecules. A well adapted growth technique seems to be the so called Gas Source MBE (GSMBE) which uses a solid In source and precracked PH 3 . The absence of a decomposition limiting process at the growing surface allows the use of substrate temperatures as low as room temperature. In this communication we will concentrate on the structural and defect analysis of InP layers grown at low temper
Data Loading...
