| AVS 61st International Symposium & Exhibition | |
| 2D Materials Focus Topic | Thursday Sessions |
| Session 2D-ThP |
| Session: | 2D Materials Poster Session |
| Presenter: | Melissa Mederos Vidal, Federal University of ABC, Brazil |
| Authors: | M. Mederos Vidal, Federal University of ABC, Brazil S.N. Mestanza Muñoz, Federal University of ABC, Brazil I. Doi, University of Campina, Brazil J.A. Diniz, University of Campina, Brazil |
| Correspondent: | Click to Email |
Germanium nanoparticles (Ge-nps) have potential applications for electronic flash memories and light emitters in visible and near infrared wavelengths, with the main advantage of being compatible with actual device technology. It is know that, in floating gate devices, semiconductors nanoparticles are the charge-storage nodes placed in the gate oxide between the gate and de channel. Thus, as a result of the smaller bandgap, superior carries mobilities, and higher excitonic Borh radius compared to Silicon (Si), quantum confinement effects are much more obvious in Ge-nps, making this compound more ideal for memory devices. On the other hand, efficient light emission from Ge-nps in SiO2 matrix has been already demonstrated being that this can be tuned by changing the size of the nanoparticle and their existence is attributed to the presence of oxide defects, nanoparticles interface, quantum effects, Ge oxygen deficient centers, etc. So, in this context, the present wok proposes the study of the influence that the improvement of the Ge-nps quality grown in SiO2 by LPCVD under different time of deposition, have on their photoluminescence and memory characteristics. For that, measurements as Raman Spectroscopy (RS), Atomic Force Microscopy (AFM) and photoluminescence spectroscopy (PL) were carried out. All samples were made on p-type Si (100) wafer covered by a 8 nm-SiO2-thermal-layer, using a vertical CVD reactor PMC 200 Phoenix Materials Corporation. The synthesis method was realized following a two-steps process: a first step, where took place the functionalization of SiO2 surface by the deposition of Si nuclei from the SiH4 pyrolysis, and a second step, where the selective growth of Ge nps over Si nuclei happens from GeH4 pyrolysis. Fig 1 shows the Normalized PL spectra for different Ge-nps size where a shift in the PL peak position towards longer wavelengths is observed with the increase of nanoparticle-size and, a raise in the intensity of the peak can be note with the enhance of the density of nanoparticle. For the memory characterization, circular MOS capacitors with 200 μm of diameter were fabricated containing these Ge-nps. Fig 2 shows the schematic of the MOS device (a) and the C-V curve comparison between a standard MOS capacitor and one containing the Ge NPs (b). According to this Fig., can be assumed that the major contribution to the memory property of the device comes from the nanoparticles in the gate dielectric since, for the capacitor without nanoparticles hardly hysteresis is observed.