ON Semiconductor (Japan)

The paper summarizes layout considerations as well as experimental data of low voltage (50 V) trench MOSFET with integrated current sensor. Major effects responsible for errors of the sensed current as well as its current dependency are discussed. Then, layout features leading to more accurate current sensing at small current are outlined.

A very stable resistor is needed for analog integrated circuits employed in harsh automotive environments. Precision SiCr thin-film resistors have been characterized by DC and pulsed I-V measurements, high-temperature operating life, and high temperature storage stress. Maximum current density for a maximum drift of 0.1% over the product lifetime are determined. Furthermore, SiCr resistors are stressed to failure and the physical failure mechanism is analyzed.

ABSTRACTThis paper describes proposal of ReRAM switching mechanism, development of production tool for ReRAM sputtering and improvement in TaOx-ReRAM switching characteristics. We propose that a ReRAM-cell has stack a structure in which an oxygen vacancy supply layer (TaOx) and an oxygen accumulation layer (Ta2O5) sandwiched by the top and bottom electrodes. Resistance change of the ReRAM-cell is caused by the oxygen vacancies migrating between the TaOx and the Ta2O5 layers by applied voltage. This prediction corresponded to the experimental facts. The thickness of Ta2O5 film sputtered by a mass production tool had good uniformity (±1.0%) and excellent stability (±1.0%). Also the sheet resistance uniformity (1σ) of TaOx film had 3.6%. By examining the sputtering conditions, the ReRAM-cell having a Ta2O5/TaOx bi-layer operated in less than 100μA with a forming-free and had excellent endurance property to 1010 cycles at 50nsec.

Blue-violet GaN-based laser diodes have been characterized by microscopic Raman scattering to obtain temperature distributions in the chip during operation. The local temperature increased steeply in the vicinity of the light-emitting layer at distance < ∼20 μm. At injection current I = 120 mA with laser output of 150 mW, the local temperature at the light emitting layer was about 50 °C higher than that of the chip mount, 25 °C. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

30K-photocapacitance and excitation photocapacitance methods were applied to reveal the dislocation-induced deep levels in coalescent epitaxial lateral overgrowth layers of InP. Point-contact Schottky barrier junctions with small junction areas were formed on dislocated and dislocation-free regions. In the dislocation-free layers, the dominant deep level was located at Ec-1.30 eV, whereas in the dislocated area, dominant deep levels were detected at Ec-0.86 eV and 1.05 eV. A neutralized state was also detected at 0.66 eV+Ev. Excitation photocapacitance results have shown that the defect configuration coordinate diagram of the dislocation-induced deep levels was considered with large Frank-Condon shifts of 0.28 eV. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

This paper introduces an alternative dicing method to reduce lateral crack and chipping problem in dicing 100 /spl mu/m thickness wafer laminated with die attach film (DAF). Conventional single pass saw process caused lateral crack due to excessive over loading of the epoxy on the blade. To overcome this problem, an alternative method of double pass saw process was proposed to reduce the blade loading. A set of experiments was carried out to determine the saw depth of the first and second pass. Chipping and cracks were characterized using measuring scope and observed with scanning electron microscopy (SEM). Results have shown that the method is more effective and able to reduce almost 80% of the chip/lateral crack as compared to single pass process.

Approximately 100 Å thick, mirror‐like, ordered tungsten layers were fabricated on (100) GaAs with chemical vapor deposition, using a precursor. Native oxides on GaAs were reduced with pretreatment in a chemical vapor deposition chamber of tungsten. Secondary ion mass spectrometry and Rutherford backscattering spectroscopy analyses indicate tungsten‐GaAs mixed layer not thicker than 20 Å. The chemical vapor deposited tungsten was applied to fabrication of state of the art, low resistance contacts to GaAs layers grown with molecular layer epitaxy. Optimization of GaAs doping, pretreatment, and tungsten chemical vapor deposition conditions were necessary to obtain low contact resistance. Contact resistance, measured with the transmission line method, was to Te doped n‐type GaAs and below to C doped p‐type GaAs. Electrically active donor/acceptor concentrations in GaAs layers grown by molecular layer epitaxy were about one order of magnitude lower than expected from literature trend lines for these contact resistance. © 1999 The Electrochemical Society. All rights reserved.