Separation of the effects of rf sources used for biasing the wafer and for sustaining the plasma is studied by measuring the space profiles of net excitation rate of Ar(3p5) for a two-frequency capacitively coupled plasma as a representation of a typical oxide etcher. Measurements were performed in Ar and in CF4/Ar mixtures. For biasing supply operating at low frequency, 700 kHz, it was shown that the effect of the voltage becomes significantly smaller as the sustaining voltage is changed from high frequency, 13.56 MHz, to very high frequency (VHF), 100 MHz, and it even disappears for pulsed operation in mixtures. This is the result of the low dc self-bias at the VHF electrode that allows the high energy secondary electrons to leave the plasma without excessive contribution to ionization and dissociation.

Neuronal networks are dynamically modified by selective synapse pruning during development and adulthood. However, how certain connections win the competition with others and are subsequently maintained is not fully understood. Here, we show that C1ql1, a member of the C1q family of proteins, is provided by climbing fibers (CFs) and serves as a crucial anterograde signal to determine and maintain the single-winner CF in the mouse cerebellum throughout development and adulthood. C1ql1 specifically binds to the brain-specific angiogenesis inhibitor 3 (Bai3), which is a member of the cell-adhesion G-protein-coupled receptor family and expressed on postsynaptic Purkinje cells. C1ql1-Bai3 signaling is required for motor learning but not for gross motor performance or coordination. Because related family members of C1ql1 and Bai3 are expressed in various brain regions, the mechanism described here likely applies to synapse formation, maintenance, and function in multiple neuronal circuits essential for important brain functions.

Two-dimensional images of two-frequency capacitively coupled plasma (2f-CCP) in Ar and Ar/CF4(5%) in an axisymmetric parallel plate reactor are investigated by using 2D-t optical emission spectroscopy. Spatially averaged electron density is obtained by microwave interferometry. Results are presented in the form of 2D profiles of the net excitation rate of Ar(3p5)(εex=14.5 eV) and Ar+(4p4D7/2)(εex=35.0 eV) used as a probe. Large area uniformity of plasma production driven at very high frequency (VHF) (100 MHz) and that driven at high frequency (HF) (13.56 MHz) at low pressure (∼25 mTorr) are compared and discussed under a low frequency (LF) (700 kHz) bias voltage on the wafer. The time modulation of the net excitation rate and the electron density indicate that the LF bias is considerably influential in the production of the plasma and in the confinement of high energy electrons at HF. Functional separation between plasma production in a gas phase and ion acceleration to the wafer is achieved in 2f-CCP excited at VHF (100 MHz). The addition of a small amount of CF4 to the Ar plasma improves the uniformity of the radial profile of the excitation at HF (13.56 MHz).

The axon initial segment (AIS) is a specialized domain essential for neuronal function, the formation of which begins with localization of an ankyrin-G (AnkG) scaffold. However, the mechanism directing and maintaining AnkG localization is largely unknown. In this study, we demonstrate that knockdown of microtubule cross-linking factor 1 (MTCL1) in cerebellar Purkinje cells causes loss of axonal polarity coupled with AnkG mislocalization. MTCL1 lacking MT-stabilizing activity failed to restore these defects, and stable MT bundles spanning the AIS were disorganized in knockdown cells. Interestingly, during early postnatal development, colocalization of MTCL1 with these stable MT bundles was observed prominently in the axon hillock and proximal axon. These results indicate that MTCL1-mediated formation of stable MT bundles is crucial for maintenance of AnkG localization. We also demonstrate that gene disruption results in abnormal motor coordination with Purkinje cell degeneration, and provide evidence suggesting possible involvement of MTCL1 dysfunction in the pathogenesis of spinocerebellar ataxia.

A time-modulated and time-averaged two-dimensional (2D) profile of the net excitation rate of Ar(3p5) and Ar+(4p4D7/2) was observed in capacitively coupled plasma (CCP) in Ar as a function of the driving frequency (1–100 MHz) through the use of 2D-t optical emission spectroscopy (OES). A significant improvement in the detection efficiency was achieved for the time-resolved OES. Results are presented for the basic characteristics of 2D and 2D-t profiles of the net excitation rate in Ar from 1 to 100 MHz at 1.0 Torr. For comparison, 2D profiles in CCP between high frequency (13.56 MHz) and very high frequency (100 MHz) at 0.1 Torr and 25 mTorr under the same power dissipation are discussed. The advantages of VHF operation are described and discussed based on the radial uniformity and high density in CCP at low pressure. The appearance of a local emission peak at the edge of the rf electrode is observed in CCP, which is caused by changes in the sustaining mechanism due to increases in the driving frequency.