A semiconductor light emitting device which can control of current density and can optimize current density and in which a rise in luminosity is possible, and a fabrication method of the semiconductor light emitting device are provided. A front end of the front barrel comprises a front ring formed inwardly and a retreating air inlet is provided behind the front ring. The neck seal also includes an outer section adhered to the inner section. A deposition process may use an adjustment in oxidizer flow andor partial pressure, the provision of a hydrogen-containing component, an adjustment in hydrogen-containing component flow andor partial pressure, an adjustment in deposition pressure, andor a modification of system component parameters, to control the characteristics of the dielectric film, e. Flow characteristics of hydraulic circuits are selected to provide suspension system damping for appropriate wheel control.