We operate an on-demand source of single electrons in high perpendicular magnetic fields up to 30 T, corresponding to a filling factor ν below 1/3. The device extracts and emits single charges at a tunable energy from and to a two-dimensional electron gas, brought into well defined integer and fractional quantum Hall (QH) states. We discuss ways to tune the emission energy as well as the sharpness of its distribution. We conclude that it can be used for sensitive electrical transport studies, e.g.of excitations and relaxation processes in QH edge states.

The Monte Carlo method is applied in this paper to characterize the noise spectra of GaAs and GaN Schottky barrier diodes operating under static and time varying conditions. We show the influence of the structure of the diode and working regimes on the noise spectrum of the diodes. Besides, the paper evaluates the capabilities of published analytical models to describe the noise spectra in Schottky diodes under time varying conditions. This is a further step toward the development of a design tool that integrates both the electrical response and the intrinsic noise generated in the devices.

Al ion implantation of chemical-vapor deposition (CVD)-grown n-type films has been used to fabricate p ⁺–n junctions for nuclear particle detectors. The junction formation mode is characterized by a high dose of Al ions and a short-duration (15 s) activating annealing. Specific structural features of the implanted p ⁺–n junctions, revealed using modern analytical techniques, are accounted for by the joint action of the high-dose Al ion implantation and unconventional rapid thermal annealing mode. The detector characteristics were studied up to a temperature of 375 °C under irradiation with 3–8 MeV alpha particles in a vacuum chamber of special design. An improvement of the energy resolution and nonequilibrium charge collection efficiency was observed with increasing temperature. The results obtained are explained in terms of specific structural features of the p ⁺–n junctions formed in the chosen implantation and thermal annealing modes. The behavior...

We report on the gating in GaAs–(Al,Ga)As heterostructures using the electrical double layer of ionic liquids. We employ tetrabutylammonium bis(trifluoromethylsulfonyl)imide for the ionic liquid, which has a melting point of 92 °C. As the 'ionic liquid' is solid at room temperature, the device operation is more stable compared to when an aqueous electrolyte is used. Hysteretic behavior appeared in the variation of the resistance when the negative gate bias exceeded ~−3 V, which is considered to be the electrochemical window of the ionic liquid. Temporary gate degradation occurred when the positive gate bias was larger than 8 V. We attribute these characteristics to the generation of space charge and its slow dissipation in the ionic liquid. The gating ceases to function at low temperatures with a transition range of 100–200 K due to the freezing of ions.

This paper addresses electromagnetic field stress effects on SiGe heterojunction bipolar transistors (HBTs)' reliability issues, focusing on the relationship between the stress-induced current and device structure degradations. The origin of leakage currents and electrical parameter shifts in failed transistors has been studied by complementary failure analysis techniques. Characterization of the structure before and after ageing was performed by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). For the stressed samples, interface deformations of the titanium (Ti) thin film around all gold (Au) contacts have been clearly detected. These degradations include localized interface reaction between Au and Ti layers as well as their lateral atomic migration causing a significant reduction of Ti thickness. EDS analysis of the disordered region which is near the Si ₃N ₄ interface has shown significant signals from Au. These observations ...

The behavior of Cu contamination at the backside surface of a thinned wafer in a three-dimensional (3D) LSI was electrically evaluated by capacitance–time ( C–t) analysis. In order to electrically evaluate Cu diffusion characteristics, MOS capacitors were fabricated using the thinned wafer of 50 µm and 100 µm thickness, respectively. For an accelerated Cu diffusion test, a thin Cu layer was deposited at the back surface as a contamination source. Cu atoms were artificially diffused into the substrate by annealing at 200 °C and 300 °C for various times in nitrogen ambient. The C–t curves of a MOS capacitor formed on a 100 µm thickness substrate were degraded even after annealing at 200 °C. It means that Cu atoms diffuse into the active region and reach the Si–SiO ₂ interface during relatively low-temperature annealing. By increasing time and temperature, the transient time t _f is more seriously decreased. The C–t curves of the MOS cap...

We present measurements of the energy relaxation time, τ _ε, of electrons in a single heterojunction in a quasi-equilibrium state using microwave time-resolved spectroscopy at 4.2 K. We find the relaxation time has a power-law dependence on the carrier density of the two-dimensional electron gas, τ _ε∝ n ^γ _s with γ = 0.40 ± 0.02 for values of the carrier density, n _s, from 1.6 × 10 ¹¹ to 6.6 × 10 ¹¹cm ⁻². The results are in good agreement with predictions taking into account the scattering of the carriers by both piezoelectric and deformation potential acoustic phonons. We compare these results with indirect measurements of the energy relaxation time from energy loss measurements involving Joule heating of the electron gas.

In circuit restructuration, it is often needed to create antifuse links, consisting in the formation of a connection between two adjacent metallic layers. These can be created by focusing a laser at a relatively high intensity to ensure efficient link creation. In order to minimize the optical power delivered in the chip from the pump laser, we have developed a novel optical in situ technique consisting of probing the link formation with a second laser beam. A sudden increase in the probe reflectance signal occurs when the metal fills the gap. By slowly increasing the pump laser beam power, it is possible to stop the intervention just after the link creation, thus minimizing the optical power delivered to the chip during the laser linking process.