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Rare earth doped metal-oxide-semiconductor (MOS) structures are of great interest for Si-based light emission. However, several physical limitations make it difficult to achieve the performance of light emitters based on compound semiconductors. To address this point, in this work the electroluminescence (EL) excitation and quenching mechanism of Er-implanted MOS structures with different designs of the dielectric stack are investigated. The devices usually consist of an injection layer made of SiO2 and an Er-implanted layer made of SiO2, Si-rich SiO2, silicon nitride, or Si-rich silicon nitride. All structures implanted with Er show intense EL around 1540 nm with EL power efficiencies in the order of 2 x 10-3 (for SiO2:Er) or 2 x 10-4 (all other matrices) for lower current densities. The EL is excited by the impact of hot electrons with an excitation cross section in the range of 0.5-1.5 x 10-15 cm-2. Whereas the fraction of potentially excitable Er ions in SiO2 can reach values up to 50%, five times lower values were observed for other matrices. The decrease of the EL decay time for devices with Si-rich SiO2 or Si nitride compared to SiO2 as host matrix implies an increase of the number of defects adding additional non-radiative de-excitation paths for Er3+. For all investigated devices, EL quenching cross sections in the 10-20 cm² range and charge-to-breakdown values in the range of 1-10 C cm-2 were measured. For the present design with a SiO2 acceleration layer, thickness reduction and the use of different host matrices did not improve the EL power efficiency or the operation lifetime, but strongly lowered the operation voltage needed to achieve intense EL. [ABSTRACT FROM AUTHOR]

The electrical properties of light-emitting field-effect transistors with Er3+ doped gate oxides formed either by a Si-rich oxide or by a SiO2 are studied. Measured output and transfer characteristics in combination with C- V curves allowed for the main device parameters determination (flat-band voltage, Debye length, or low-field mobility). Decreased threshold voltage, interface charge trapping and low-field mobility enhancement in devices containing Si-rich oxides respect to those with Er3+ doped SiO2 gate are found. In addition, the implantation of Er3+ ions in the gate oxide produced significant low-field mobility reduction in the transistor inversion layer. Typical polarization scheme and device cross section of a light-emitting field-effect transistor (left). Erbium electroluminescence spectrum collected from the top of the polysilicon gate (right). [ABSTRACT FROM AUTHOR]

Electro-optical properties of a multilayer structure composed by silicon-rich silicon oxide (SiOX), silicon oxide (SiO2) and silicon-rich silicon nitride (SiNX) are studied on this work. A 12% Si excess has been introduced by means of ion implantation in both SiOX and SiNX layers. The electrical characterization allowed us to identify as Poole-Frenkel the main electrical transport mechanism which governs these structures. In addition, remarkable enhancement to the electroluminescence emission was provided by increasing the accelerator layer thickness (intermediated SiO2). The results open new routes toward the design and development of integrated Si-based light emitters. [ABSTRACT FROM AUTHOR]