Recent articles have been published claiming that the ambipolar diffusion coefficient of semiconductors, Da, is basically independent of the excess-carrier concentration, thus contradicting the conventional result of, for example, Fletcher. However, only a few experimentally verified papers on this subject are published. In the present work, a detailed experimental analysis of the ambipolar diffusion coefficient is presented regarding both temperature and injection-level dependence. The ambipolar diffusion coefficient was measured in the low-doped n base of a p-i-n type diode at different excess-carrier concentrations and temperatures using an open-circuit carrier decay (OCCD) method based on the free-carrier absorption (FCA) technique. This investigation was performed in the carrier-concentration range of 1015–2×1017 cm−3 and in the temperature range of 300–420 K, respectively. The ambipolar diffusion coefficient is experimentally found to behave in reasonable agreement with Fletcher’s theory, thus decreasing with increasing excess-carrier concentration.

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Deep level transient spectroscopy measurements of electron traps in MeV proton- and alpha-irradiated n-type silicon have been performed. Six deep levels are found in proton-irradiated samples, while only three appear after alpha irradiation. The influence of the irradiation dose on the defect production is investigated together with the depth concentration profiles. The profiles scale with the nuclear energy deposition, but in the case of the doubly negative charged state of the divacancy at EC −0.24 eV, the peak concentration at the end of the track is less pronounced relative to the tail region towards the surface. It is proposed that the singly negative charged state at EC −0.42 is more probable in a highly distorted lattice and it is shown that the formation of the singly negative charged state of the divacancy dominates the defect production for higher doses.

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Sigma7l 00 is a revolutionary new architecture for Laser Pattern Generators being developed by Micronic Laser Systems. The Sigma7iOO system design uses a unique architecture based on a spatial light modulator (SLM), a MEMS consisting of a 1 million pixel micro-mirror array fabricated onto a CMOS substrate. The SLM functions as a dynamic mask which is illuminated by a 1 kHz DUV excimer laser. A new pattern is calculated and downloaded into the SLM for each laser pulse, and the resultant SLM image is then projected onto the mask substrate. This paper describes the Sigma7i 00 architecture, presents recent results, and presents a look into the path toward extending the SLM technology to the 7Onm node and beyond. Advantages to an SLM mask writerThe growing consensus within the semiconductor lithographic community is for deep ultra violet (DUV) optical technology for the next mask writing tool. A DUV optical mask writing tool would exploit the technology developed for optical steppers, from excimer light sources and optics to DUV sensitive resists and processes. Conversely, E-beam technology continues to suffer from the fundamental limitations on coulomb interaction, proximity effects, heat transfer, and throughput.