Papers by Keyword: Heavy Doping

Abstract: To determine the electrically inactive fraction of As or P in heavily doped as-grown Czochralski Si 4-point resistivity and SIMS measurements were carried out. No clear trend for the electrical inactive fraction was found with an increasing dopant concentration, though a mean electrical inactive fraction of 11.5% for As doping could be determined.Experimental results on a dopant-vacancy complex in as-grown Si are scarce, hence temperature-dependent positron annihilation lifetime spectroscopy (PALS) was carried out on several heavily As and P doped as-grown Si samples. The measured average positron annihilation lifetime τ_av is between 218 ps and 220 ps. No temperature dependent effect on τ_av could be observed. Therefore, it can be concluded that in the studied doping range the dopant-vacancy complexes do not exist. The reason for the inactivation of the dopant has to be found elsewhere. A possible explanation can be the formation of dopant precipitates.

Abstract: A new kind of SOI LAPS sensor array with trench and heavy doping structure was proposed. Photo current response, noise isolation and device performance were simulated with ISE-TCAD tools. The new structure LAPS sensor array effectively improves noise separation characteristics of adjacent array units. The SNR (signal-to-noise ratio) of LAPS array with trench-isolated structure is superior to that with only heavy doping regions. Trench isolation structure also improves the integration scales of LAPS array.

Abstract: The defect evolution on 90 μm-thick heavily Al-doped 4H-SiC epilayers with Al doping level higher than 10²⁰ cm^-3 was studied by tracing back to initial growth stage to monitor major dislocations and their propagations in each growth stage. Results from X-ray topography and KOH etching demonstrate that all existing dislocations on the surface of 90 μm-thick epilayer can be identified as the defects originating from substrate. In other words, there seems no new dislocation generated after a long-term growth. Nevertheless, a high density of misfit dislocation was found appearing near the substrate/epilayer interface for epilayer with Al doping level of 3.5×10²⁰ cm^-3, while misfit dislocation cannot be seen on epilayer with Al doping level of 1.5×10²⁰ cm^-3.

Abstract: We calculated the Seebeck coefficient of heavily-doped Si based on theoretical models of impurity-band formation, ionization-energy shift and conduction-band tailing. The impurity band was described by using two kinds of band-width definitions and it was found that the calculated Seebeck coefficient strongly depended on the impurity-band definition. In the high impurity-concentration region, the Seebeck coefficient decreased with increasing impurity concentration, and with a peak around 1×1019 cm-3. This result was qualitatively in good agreement with the experimental result, while there was quantitative disagreement between them.