Millisecond laser annealing is used to fabricate ultra shallow arsenic junctions in preamorphized and crystalline germanium, with peak temperatures up to 900°C. At this temperature, As indiffusion is observed while yielding an electrically active concentration up to 5.0 ϫ 10 19 cm −3 for a junction depth of 31 nm. Ge preamorphization and the consecutive solid phase epitaxial regrowth are shown to result in less diffusion and increased electrical activation. The recrystallization of the amorphized Ge layer during laser annealing is studied using transmission electron microscopy and spectroscopic ellipsometry.Germanium has received considerable attention in the last decade as a promising channel material for high performance logic applications. However, as scaling continues the source/drain resistance gains in importance. 1,2 Consequently, ultra shallow and low resistive junctions are required for the integration into very-large scale integration circuitry.Shallow, low resistive p-type junctions ͑using B or Ga as acceptors͒ can be attained using optimized solid phase epitaxial regrowth ͑SPER͒ and rapid thermal annealing ͑RTA͒ schemes. 3,4 In contrast, donors such as P or As show high concentration-enhanced diffusion; 5 a mechanism which has been consistently explained by mobile, negatively charged dopant-vacancy pairs. 6 The fabrication of ultra shallow junctions therefore requires a limited thermal budget ͑low temperature or fast anneal͒, while a high temperature is still needed to achieve a high electrically active concentration. These two competing requirements have led to the use of ultrafast heattreatment methods such as flash-assisted annealing 7-9 and millisecond laser thermal processing. Previously, laser annealed P junctions in Ge ͑X J Ͼ 70 nm͒ were investigated. 10,11 In this work, we investigate the feasibility of laser annealing to fabricate ultra shallow, low resistive As junctions in germanium. More specifically, the effects of the laser peak temperature and the combination with a preamorphization implant are studied.As junctions were fabricated using p-type, 300 mm, ͑100͒-oriented Si wafers on which a relaxed epitaxial Ge was grown ͑1.5 m thick, threading dislocation density Ϸ2 ϫ 10 7 cm −2 ͒ and capped with 2 nm of GeO 2 ͓which was stripped preceding secondary-ion mass spectroscopy ͑SIMS͒ and micro four-point probe tool ͑u4PP͒ analysis͔. The wafers received a boron well doping up to 3 ϫ 10 17 cm −3 , followed by a Ge preamorphization implant ͑PAI-Ge 20 keV, 2 ϫ 10 14 cm −2 ͒ on selected samples, yielding an amorphous layer of 25 nm. As was implanted at an energy of 5 keV ͑5 ϫ 10 14 cm −2 ͒. The samples then received millisecond laser annealing. The laser spot measures 1.1 cm ϫ 75 m and scans the wafer at a speed of 75 mm/s ͑two consecutive scans͒. A wafer preheating is applied ͑250°C͒ to reduce thermal stress arising from the localized laser heating. No absorber layer was deposited to assist in the laser anneal. Multiple regions ͑each measuring at least 5 ϫ 5 cm͒ were illuminated, whereby the laser ...

The successful implementation of nanowire (NW) based field-effect transistors (FET) critically depends on quantitative information about the carrier distribution inside such devices. Therefore, we have developed a method based on high-vacuum scanning spreading resistance microscopy (HV-SSRM) which allows two-dimensional (2D) quantitative carrier profiling of fully integrated silicon NW-based tunnel-FETs (TFETs) with 2 nm spatial resolution. The key elements of our characterization procedure are optimized NW cleaving and polishing steps, the use of in-house fabricated ultra-sharp diamond tips, measurements in high vacuum and a dedicated quantification procedure accounting for the Schottky-like tip-sample contact affected by surface states. In the case of the implanted TFET source regions we find a strong NW diameter dependence of conformality, junction abruptness and gate overlap, quantitatively in agreement with process simulations. In contrast, the arsenic doped drain regions reveal an unexpected NW diameter dependent dopant deactivation. The observed lower drain doping for smaller diameters is reflected in the device characteristics by lower TFET off-currents, as measured experimentally and confirmed by device simulations.

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