Next generation low temperature polycrystalline materials for above IC electronics. High mobility n- and p-type III-V metalorganic vapour phase epitaxy thin films on amorphous substrates

• Published in: JPhys photonics Vol. 2; no. 2; pp. 25003 - 25017
• Main Authors: Gocalinska, Agnieszka, Pescaglini, Andrea, Secco, Eleonora, Mura, Enrica E, Thomas, Kevin, Curran, Anya, Gity, Farzan, Nagle, Roger, Schmidt, Michael, Micha owski, Pawe P, Hurley, Paul K, Povey, Ian, Pelucchi, Emanuele
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 02.03.2020
• Subjects: Charge density; Electron density; Epitaxial growth; Field effect transistors; GaAs; Gallium antimonides; Gallium arsenide; GaSb; Glass substrates; Heterostructures; Hole mobility; III-V; InAs; Integrated circuits; Low temperature; low temperature growth; Metalorganic chemical vapor deposition; metalorganic vapour phase epitaxy; polycrystalline; Polycrystals; Room temperature; Semiconductor devices; Silicon dioxide; Silicon substrates; Temperature; Thickness; Thin films; Vapor phase epitaxy; Vapor phases
• ISSN: 2515-7647; 2515-7647
• DOI: 10.1088/2515-7647/ab7557

We report on the growth and electronic properties of polycrystalline III-V semiconductors, which to date have not been discussed in depth in the literature. III-V polycrystalline semiconductor thin films were grown by metalorganic vapour phase epitaxy in the temperature range 410 °C-475 °C, which is compatible for integration into the Back-End-Of-Line (BEOL) silicon based integrated circuits. The thickness of the films in this study is in the range of tens to a few hundreds of nanometers, and deposited on amorphous substrates (either smart-phone-grade glass or Si/SiO2) and, also, on oxidised GaAs epi-ready wafers. Extensive AFM, SEM and TEM analyses show interlinked-to-continuous polycrystalline III-V films based on In(Al)As or GaSb. Hall-van der Pauw measurements return results of high mobility and controllable charge density for n- and p-type field effect transistors. In the GaAs/In(Al)As system, electron density ranging from 1 × 1016 to 1 × 1019 cm−3 (n) was achieved, with room temperature mobility values in the range of 100-150 cm2 V−1 s−1 and hole mobility values in the range of 1-10 cm2 V−1 s−1 have been measured in Zn doped samples. Polycrystalline GaSb films demonstrated p-type behaviour (1 × 1017 cm−3) with remarkably high room temperature hole mobility values up to 66 cm2 V−1 s−1 for the films grown on Si/SiO2 substrate (and 300 cm2 V−1 s−1 for the GaAs substrate where an epitaxial process is actually in place). Materials could be stacked into heterostructures, providing a promising platform for complex devices enabling compatible n- and p- hetero-layers for 3D integration formed at temperatures ≤480 °C.