| AVS 56th International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures | Thursday Sessions |
| Session MI-ThP |
| Session: | Magnetic Interfaces and Nanostructures Poster Session |
| Presenter: | J.R. Abel, University at Albany |
| Authors: | J.R. Abel, University at Albany J.J. Garramone, University at Albany E. Bersch, University at Albany A.C Diebold, University at Albany V.P. LaBella, University at Albany |
| Correspondent: | Click to Email |
Aluminum oxide can be utilized as an interface layer between ferromagnetic metals and silicon to achieve spin injection into silicon. Utilizing the spin of the electron as well as its charge has the potential to be utilized for logic devices in the post CMOS era. The goal of our research is to inject and readout spins using a non-local measurement device that utilizes 1-2 nm aluminum oxide interface layers as tunnel barriers.
The first step of fabricating a non-local measurement device out of silicon is the growth of an aluminum oxide tunnel barrier1. Si (001) wafers were dipped in 49% HF solution for approximately 2 min to remove the native oxide layer. The wafers were then immediately loaded into an ultrahigh vacuum MBE machine, degassed at 400 C and cooled to room temperature. After cooling, a desired thickness of aluminum was deposited from a Knudsen cell. The sample was then transferred back into the load lock and exposed to approximately 130 mTorr of pure O2 for 20 min. The process was repeated to create samples with a thickness of 1 nm, 2 nm, and 3 nm of aluminum oxide. Each thickness was grown in 0.5 nm and 1 nm steps. In addition, a 2 nm sample was grown, in one 2 nm step.
X-ray photoelectron spectroscopy was performed to characterize the film stoichiometry. It was observed that all the aluminum was bonded to the oxygen for the films grown in 0.5 nm and 1 nm steps. Whereas the 2 nm sample grown in one 2 nm step not all the aluminum bonded to oxygen, leaving a partially un-oxidized aluminum film. In addition XPS was used to measure the band gap of the fully oxidized films to be 6.61 eV in good agreement with films of similar thickness2. We will also report on current voltage measurements of these films after they have been capped with metal and application of “Rowell criteria” to demonstrate tunneling as the dominant transport mechanism.
References:
[1] O. van’t Erve, A. Hanbicki, M. Holub, C. Li, C. Awo-Affouda, P. Thompson and B. Jonker, Appl. Phys. Lett. 91, 212109 (2007).
[2] H.Y. Yu, et al., Appl. Phys. Lett., 81:376, 2002