Oxidation-Induced Changes in the ALD-Al2O3/InAs(100) Interface and Control of the Changes for Device Processing
Tuominen, Marjukka; Mäkelä, Jaakko; Yasir, Muhammad; Dahl, Johnny; Granroth, Sari; Lehtiö, Juha Pekka; Félix, Roberto; Laukkanen, Pekka; Kuzmin, Mikhail; Laitinen, Mikko; Punkkinen, Marko P.J.; Hedman, Hannu Pekka; Punkkinen, Risto; Polojärvi, Ville; Lyytikäinen, Jari; Tukiainen, Antti; Guina, Mircea; Kokko, Kalevi (2018-12-26)
Tuominen, Marjukka
Mäkelä, Jaakko
Yasir, Muhammad
Dahl, Johnny
Granroth, Sari
Lehtiö, Juha Pekka
Félix, Roberto
Laukkanen, Pekka
Kuzmin, Mikhail
Laitinen, Mikko
Punkkinen, Marko P.J.
Hedman, Hannu Pekka
Punkkinen, Risto
Polojärvi, Ville
Lyytikäinen, Jari
Tukiainen, Antti
Guina, Mircea
Kokko, Kalevi
26.12.2018
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-201912307140
https://urn.fi/URN:NBN:fi:tuni-201912307140
Kuvaus
Peer reviewed
Tiivistelmä
InAs crystals are emerging materials for various devices like radio frequency transistors and infrared sensors. Control of oxidation-induced changes is essential for decreasing amounts of the harmful InAs surface (or interface) defects because it is hard to avoid the energetically favored oxidation of InAs surface parts in device processing. We have characterized atomic-layer-deposition (ALD) grown Al2O3/InAs interfaces, preoxidized differently, with synchrotron hard X-ray photoelectron spectroscopy (HAXPES), low-energy electron diffraction, scanning tunneling microscopy, and time-of-flight elastic recoil detection analysis. The chemical environment and core-level shifts are clarified for well-embedded InAs interfaces (12 nm Al2O3) to avoid, in particular, effects of a significant potential change at the vacuum-solid interface. High-resolution As 3d spectra reveal that the Al2O3/InAs interface, which was sputter-cleaned before ALD, includes +1.0 eV shift, whereas As 3d of the preoxidized (3 × 1)-O interface exhibits a shift of -0.51 eV. The measurements also indicate that an As2O3 type structure is not crucial in controlling defect densities. Regarding In 4d measurements, the sputtered InAs interface includes only a +0.29 eV shift, while the In 4d shift around -0.3 eV is found to be inherent for the crystalline oxidized interfaces. Thus, the negative shifts, which have been usually associated with dangling bonds, are not necessarily an indication of such point defects as previously expected. In contrast, the negative shifts can arise from bonding with O atoms. Therefore, specific care should be directed in determining the bulk-component positions in photoelectron studies. Finally, we present an approach to transfer the InAs oxidation results to a device process of high electron mobility transistors (HEMT) using an As-rich III-V surface and In deposition. The approach is found to decrease a gate leakage current of HEMT without losing the gate controllability.
Kokoelmat
- TUNICRIS-julkaisut [17098]