Toward the controlled synthesis of hexagonal boron nitride films.

Atomically smooth hexagonal boron nitride (h-BN) layers have very useful properties and thus potential applications for protective coatings, deep ultraviolet (DUV) emitters, and as a dielectric for nanoelectronics devices. In this paper, we report on the growth of h-BN by a low-pressure chemical vapor deposition (LPCVD) process using diborane and ammonia as the gas precursors. The use of LPCVD allows synthesis of h-BN with a controlled number of layers defined by the growth conditions, temperature, time, and gas partial pressure.

Room-temperature quantum confinement effects in transport properties of ultrathin Si nanowire field-effect transistors.

Quantum confinement of carriers has a substantial impact on nanoscale device operations. We present electrical transport analysis for lithographically fabricated sub-5 nm thick Si nanowire field-effect transistors and show that confinement-induced quantum oscillations prevail at 300 K. Our results discern the basis of recent observations of performance enhancement in ultrathin Si nanowire field-effect transistors and provide direct experimental evidence for theoretical predictions of enhanced carrier mobility in strongly confined nanowire devices.

Quantum confinement induced performance enhancement in sub-5-nm lithographic Si nanowire transistors.

We demonstrate lithographically fabricated Si nanowire field effect transistors (FETs) with long Si nanowires of tiny cross sectional size (∼3-5 nm) exhibiting high performance without employing complementarily doped junctions or high channel doping. These nanowire FETs show high peak hole mobility (as high as over 1200 cm(2)/(V s)), current density, and drive current as well as low drain leakage current and high on/off ratio. Comparison of nanowire FETs with nanobelt FETs shows enhanced performance is a result of significant quantum confinement in these 3-5 nm wires.

The focused ion beam fold-out: sample preparation method for transmission electron microscopy.

We have developed the focused ion beam (FIB) fold-out technique, for transmission electron microscopy (TEM) sample preparation in which there is no fine polishing or dimpling, thus saving turnaround time. It does not require a nanomanipulator yet is still site specific. The sample wafer is cut to shape, polished down, and then placed in a FIB system.