T. Wilhelm

A pure 1.5 μm electroluminescence from metal-oxide-silicon tunneling diode using dislocation network

This letter has demonstrated a light emitting diode (LED) with a pure 1.5 μm emission using a metal-oxide-silicon (MOS) tunneling structure based on dislocation network in direct silicon bond wafer. It is found that under negative gate bias, the electrons in the metal gate electrode tunnel through the thin oxide to silicon and then recombine radiatively with holes at the dislocation related states to emit the D1-line with a wavelength of 1.5 μm. The calculation of energy band diagram indicates that a potential well for electrons forms at the charged bonding interface under negative bias, therefore, the electrons tunneled from the gate can rapidly be attracted by the electric field and then confined at the interface, which essentially increases the efficiency of D1 luminescence from MOS tunneling LED. These results are of interest for the development of silicon based photonics with 1.5 μm light emission.

Regular Dislocation Networks in Silicon Part I: Structure

Dislocation networks obtained by hydrophobic wafer bonding of Si (100) are investigated. The twist and tilt misorientations induce two interacting dislocation networks. Advanced bonding techniques are applied and optimized allowing to eliminate the tilt and to control the twist misorientation. At very low twist angles the interfaces no longer exhibit regular dislocation networks. Properties of dislocation networks are discussed.

Regular Dislocation Networks in Si. Part II: Luminescence

Regular dislocation networks formed as a result of the direct bonding of Cz-Si wafers with oxide remnants on the pre-bonding surfaces were investigated. Besides the dislocation network, oxide precipitates were detected at the bonding interface. The precipitate density across the network was ~5×1010 cm-2, except small irregularly distributed circular areas, several mm in diameter, where the density was remarkably lower (<5×108 cm-2). The dislocation network structure was not affected by the change in the precipitate density. Photoluminescence spectroscopy (PL) and light beam induced current (LBIC) mapping were applied for characterization of such dislocation networks. For the locations with high precipitate density, PL signal from dislocations and that from the band-to-band transitions were enhanced. On the other hand, the LBIC results indicated that oxide precipitates are active recombination centers and thus should suppress the observed radiative transitions. The controversy can be explained in the assumption that the D-band PL signal increases due to scattering of excitation light by the precipitates and due to related expansion of the excitation area of the dislocation network. The light reflection from the precipitate layer also enhances the detected band-to-band PL signal. The shape of PL spectra from the samples in the range of photon energies 0.75 – 1.15 eV was not influenced by the oxide precipitates.

Regular Dislocation Networks in Silicon as a Tool for Novel Device Application

The paper deals with possibilities of utilizing dislocation structures as active components of devices. The suggested means for controlled formation of dislocations is direct wafer bonding, giving rise to well defined dislocation networks with adjustable properties. It is shown that the networks allow building light emitting diodes based on the D line luminescence of the dislocations. A light emitter at about 1.5 mm wavelength is demonstrated, with an efficiency potential estimated at 1%. Immobilization of biomolecules on Si surfaces by Coulomb interaction with the dislocations in the network is another application discussed. Finally, the potential use of dislocation networks as insulating layers permeable to impurities to be gettered and as three-dimensional buried conductive channels in the Si wafer is addressed.

Dislocations in Silicon as a Tool to Be Used in Optics, Electronics and Biology

M. Kittler, M. Reiche, T. Arguirov, T. Mchedlidze, W. Seifert, O.F. Vyvenko, T. Wilhelm, X. Yu 1 IHP, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany 2 IHP/BTU Joint Lab, Konrad-Wachsmann-Allee 1, 03046 Cottbus, Germany 3 MPI für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany 4 St. Petersburg State University, Uljanovskaja 1, 198904 St. Petersburg, Russia a kittler@ihp-ffo.de; b reiche@mpi-halle.de; c vyvenko@paloma.spbu.ru

1.5 μm Emission from a Silicon MOS-LED Based on a Dislocation Network

A novel Si MOS-LED is demonstrated, which is fully compatible with Si technology. It is based on a dislocation network fabricated by wafer direct bonding. Light emission at 1.5 μm was observed when the network was near the Si/SiO2 interface close to/inside the accumulation layer induced by the gate voltage

Stark effect at dislocations in silicon for modulation of a 1.5 μm light emitter

A MOS-LED and a p-n LED emitting based on the dislocation-related luminescence (DRL) at 1.5 micron were already demonstrated by the authors. Here we report recent observation of the Stark effect for the DRL in Si. Namely, a red/blue-shift of the DRL peak positions was observed in electro- and photo-luminescence when the electric field in the pn-LED was increased/lowered. Fitting the experimental data yields a strong characteristic coefficient of 0.0186 meV/(kV/cm)2. This effect may allow realization of a novel Si-based emitter and modulator combined in a single device.

Light Emission by Dislocations in Silicon

Different approaches for Si-based light emitters were studied. The D band emission of dislocations formed by wafer bonding is a promising candidate for spatially confirmed emitters at 1.3mum leslambdales1.5mum