During evaluation of negative bias temperature instability (NBTI) in short-channel devices, we found that using an optimized nitrogen depth profile is important in suppressing NBTI when scaling down CMOS devices. Performing the NO anneal process before oxidation yeilds good transistor performance, suppressing NBTI by 25%. When using more nitrogen to moderate gate leakage and boron penetration, in addition to the amount of nitrogen, it is important to control the depth profile of the nitrogen on gate insulator, as our research shows that the interface peak concentration of nitrogen enhances NBTI degradation.Index Terms-Gate insulator, MOSFET, negative bias temperature instability (NBTI), nitrogen depth profile, NO annealing, SiO2.

A few seconds halogen lamp annealing (HLA) technology is evaluated from the viewpoint of practical application to complementary metal oxide semiconductor (CMOS) very large scale integration (VLSI) processing. 49BF2 , 11B, and 31P ion‐implanted silicon layers have been investigated on their isothermal short‐time annealing behavior of junction leakage current, recrystallization, activation, and junction depth. We have found that a few seconds annealing of 800°C is enough to crystalline regrow the 49BF2 or 31P ion‐implanted amorphous layer, to activate 49BF2 or 31P ion‐implanted dopants, to form titanium silicide, and to reduce the area leakage current of both n+‐p− and p+‐n− junctions without dopant diffusion. But activation of 11B+ ion‐implanted dopants, reduction of perimeter leakage current, molybdenum silicide formation, and phosphosilicate glass (PSG) reflow require a little higher temperature heat‐treatment.

The diffusion of boron in MoSi2 films has been studied. The diffusion is determined by a combination of two factors: the low diffusivity in the bulk of grains and the much higher diffusivity in the grain boundaries. The diffusivity in the bulk of grains was 1×10−14 cm2/s and 8×10−13 cm2/s for furnace annealing at 950 °C and halogen lamp annealing at 1060 °C, respectively. The diffusivity in the grain boundaries was over two orders of magnitude higher than that in the bulk of grains. High-temperature annealing of MoSi2 films reduce the solubility and diffusivity of boron in the films because of grain growth.

The aim of this study is to develop a new light collimator with almost the same efficiency in terms of photon penetration as that of the conventional collimator. Generally, the conventional collimator is an over specification in terms of the path length in the material forming the collimator. If the path length of a gamma-ray in the septum is short, many photons may pass through the septum and the septum does not work as a shielding material. On the other hand, if we consider a path located near the center of the septum, it is sufficient to shield from undesirable gamma-rays. So we gave up using the plane-septum structure that is used in the conventional collimator. In the new collimator we made several spaces where the septa located in the conventional collimator. One realistic form of the collimator is composed of many rods whose cross-section is square or circular. The collimator is composed of rod-shaped lead or tungsten in -and -directions alternately with spacing in the -direction (direction of thickness). Even though we align many rods alternately without spacing in -direction, we can achieve a collimator with less than half the weight of a conventional collimator. Performance of the proposed collimator was confirmed by Monte Carlo simulation and experiments with a handmade collimator.