双波长Nd：YAG脉冲激光器的实验研究

根据多波长同时振荡条件，我们建立了大能量１０６４ｎｍ和１３１８ｎｍ同时运转的双波长脉冲Ｎｄ：ＹＡＧ激光器。得到了１０６４ｎｍ和１３１８ｎｍ的激光输出能量分别为０．５９４Ｊ和０．８６１Ｊ，效率分别为０．３１％和０．４５％。实验结果说明了该双波长激光器有较好的时间和空间重选性。     

Suppression of boron penetration in p+ polysilicon gateP-MOSFETs using low-temperature gate-oxide N2O anneal

It has been reported that high-temperature (~1100°C) N₂ O-annealed oxide can block boron penetration from poly-Si gates to the silicon substrate. However, this high-temperature step may be inappropriate for the low thermal budgets required of deep-submicron ULSI MOSFETs. Low-temperature (900~950°C) N₂O-annealed gate oxide is also a good barrier to boron penetration. For the first time, the change in channel doping profile due to compensation of arsenic and boron ionized impurities was resolved using MOS C-V measurement techniques. It was found that the higher the nitrogen concentration incorporated at Si/SiO₂ interface, the more effective is the suppression of boron penetration. The experimental results also suggest that, for 60~110 Å gate oxides, a certain amount of nitrogen (~2.2%) incorporated near the Si/SiO₂ interface is essential to effectively prevent boron diffusing into the underlying silicon substrate     

Enhancement of oxide break-up by implantation of fluorine inpoly-Si emitter contacted p+-n shallow junctionformation

In this study, it is demonstrated that the incorporation of fluorine can enhance poly-Si/Si interfacial oxide break-up in the poly-Si emitter contacted p⁺-n shallow junction formation. The annealing temperature for breaking up the poly-Si/Si interfacial oxide has been found to be as low as 900°C. As a result, the junction depth of the BF₂-implanted device is much larger than that of the boron-implanted device     

A digital automatic current control system based on an optimumassumed model

In this paper, a new ACR (automatic current regulator) scheme is introduced for brushless DC motors. It consists of a model closely resembling the motor and PWM inverter, an assumed rising pattern of the current, and a parameter estimation. Using the control scheme, the mean value of the motor current is kept at the reference current, and the transient current of the motor is kept equal to the rising pattern. For the disturbance, because of DC-line voltage change, the proportional path from the error to the duty cycle of the PWM signal stabilizes the ACR. This ACR scheme can be realized with a microcomputer     

Evaluation technique of gate oxide damage

Gate oxide damage by plasma processing was evaluated using structures with various antenna lengths. The gate oxide damage by plasma processing was found to be monitored quantitatively by measuring the charge to breakdown, Q_BD. From the Q_BD measurements, we have confirmed that the degradation occurs during overetching, not in main etching. Plasma current was calculated from the decrease of Q_BD during the etching. The breakdown spot in the gate oxide was detected by photon emission and TEM. The LOCOS structure plays an important role for the degradation by plasma damage. In this paper, it is demonstrated that the Q_BD method is effective for realizing a highly reliable process against plasma damage     

LIDAR mapping of ozone-episode dynamics in Paris and intercomparison with spot analyzers Supplementary material available at http://link.springer.de/journals/apb

Continuous mapping of an ozone episode in Paris in June 1999 has been performed using a differential absorption lidar system. The 2D ozone concentration vertical maps recorded over 33 h at the Champ de Mars are compiled in a video clip that gives access to local photochemical dynamics with unprecedented precision. The lidar data are compared over the whole period with point monitors located at 0-, 50-, and 300-m altitudes on the Eiffel Tower. Very good agreement is found when spatial resolution, acquisition time, and required concentration accuracy are optimized. Sensitivity to these parameters for successful intercomparison in urban areas is discussed. Received: 11 February 2002 / Published online: 14 March 2002     

Mechanism analysis of gate-induced drain leakage in off-state n-MOSFET

An analytical expression for both band-to-band and band-trap-band indirect tunnelings is used to study the gate-induced drain leakage (GIDL) current of MOSFETs measured before and after hot-carrier stress. The voltage and temperature dependence of GIDL are characterized. Both results show that interface traps situated near the midgap participate in the conduction of GIDL, and band-trap-band indirect tunneling could be the major mechanism. This is further supported by the fact that the percentage increase in GIDL induced by hot-carrier stress is about the same as the corresponding increase in interface-trap density. On the other hand, under low-field conditions, trap-assisted Poole–Frenkle emission dominates over tunneling for temperatures even well below room temperature.     

Ka-band solid-state pulsed Gunn oscillator and power combiner

GaAs Gunn diodes were fabricated for pulse source application at 8 mm wave band and operated with pulsewidths of 0.05 to 2.0 microseconds and duty cycles of 0.001 to 0.01. Peak pulse output power levels of 0.8–1.2W are achieved and the maximum available power is 1.6W with the highest efficiency of 6.5 percent. A simple and compact pulsed power combiner is also given in this paper.     

Latest advances in camcorder technology

Camcorders have been developed to be compact with high performance. Latest advancement of key technologies and devices such as digital signal processing LSI, six-layer printed circuit board with micro chips, high-speed power lens with linear motor, 103 K pixels 0.7-in LCD electronic viewfinder, and high-energy Li-ion battery are described. High-band format is also explained     

A new physical model of the light amplifying optical switch (LAGS)

A new physical model of determining the static I-V curve of the light amplifying optical switch (LAOS) is derived. The model is based on deriving the currents of the HPT and the feedback current of the LAOS. The feedback currents for optical and/or electrical feedback are determined by solving the continuity equation in the collector and the base of the HPT. A negative resistance region in the I-V curve is obtained and controlled by varying the feedback coefficient of the device and the Early effect coefficient. The main factors affecting the negative resistance region are the feedback coefficient, Early effect, the recombination currents in the emitter-base space-charge region, and the ratio of the collector to base doping. The switching voltage of the device is also calculated for different parameters