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Low-temperature (LT) passivation methods (< 450 o C) for decreasing defect densities in the material combination of silica (SiOx) and silicon (Si) are relevant to develop a diverse technology (e.g. electronics, photonics, medicine), where defects of SiOx/Si cause losses and malfunctions. Many device structures contain the SiOx/Si interface(s), of which defect densities cannot be decreased by the traditional, beneficial high temperature treatment (> 700 o C). Therefore, the LT passivation of SiOx/Si has been, since long, a research topic to improve applications performance. Here, we demonstrate that a LT (< 450 o C) ultrahigh-vacuum (UHV) treatment is a potential method that can be combined with current state-of-theart processes in a scalable way, to decrease the defect densities at the SiOx/Si interfaces. The studied LT-UHV approach includes a combination of wet chemistry followed by UHV-based heating and pre-oxidation of silicon surfaces. The controlled oxidation during the LT-UHV treatment is found to provide an until now not reported crystalline Si oxide phase. This crystalline SiOx phase can explain the observed decrease in the defect density by halve.Furthermore, the LT-UHV treatment can be applied in a complementary, post-treatment way to ready components to decrease electrical losses. The LT-UHV treatment has been found to decrease the detector leakage current by factor of two.

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Defects smaller than 10 nm, with number densities below 10 10 cm Ϫ2 , form spontaneously beneath ion-milled, etched, or HFdipped silicon surfaces examined in our Ti-ion getter-pumped transmission electron microscope ͑TEM͒ after exposure to air. They appear as weakly strained noncrystalline intrusions into the silicon bulk which show up best in the TEM under conditions of strong edge or bend contrast. If ambient air exposure is Ͻ10 min, defect nucleation and growth can be monitored in situ. Possible mechanisms of formation are discussed.As gigascale integrated circuit devices approach nanometer dimensions, the bulk and surface structure of single crystal silicon is attracting finer scrutiny. In this context, recent searches for bulk defects 10 nm in size required that we consider more carefully some ubiquitous but weakly strained specimen preparation artifacts that for studies of larger bulk defects we had ignored.Transmission electron microscopy ͑TEM͒ observations show that these imperfections, which form in variously oriented silicon surfaces after exposure to air, are strikingly similar after thinning with physically different methods. Moreover, the process of their formation can be slowed to laboratory time scales at room temperature if air exposure is sufficiently short. This allows in situ study of nucleation and growth, offering a view of dynamic processes in silicon which take place on laboratory time scales at room temperature, including the movement of self-interstitials and surface diffusion barrier formation. Both of these are subjects of widespread fundamental and applied interest. 1-4 ExperimentalThis study was begun on 200 mm p-type boron-doped wafers, although the results have been checked on archive specimens with a wide range of ingot diameters ͑as small as 100 mm͒, growth conditions, impurity concentrations, and thermal histories. The silicon was cut into 3 mm diam disks, mechanically thinned, and dimpled to about 20 m thickness in the center. Final thinning to perforation involved one of three methods: ͑i͒ ion-milling, in which the thinned disk was bombarded with 1 or 4 keV Ar ions at an incidence angle of 70 to 85°, until perforation; ͑ii͒ chemical etching, in which the thinned disk was put into a solution of concentrated HNO 3 :HF ϭ 3:1 until perforation, followed by a water wash; and ͑iii͒ ''HF dip'', in which a specimen already perforated by chemical etching is dipped for 30 s in concentrated 50-55% HF and then washed in deionized water to passivate surface silicon atoms with hydrogen to reduce the rate of surface oxidation.Specimens were examined in a 300 kV Philips EM430ST TEM with point resolution near 0.2 nm. A 10 m diam objective aperture was used to increase diffraction contrast, as an aid in locating otherwise nearly invisible defects. Choice of regions and orientations where strong thickness fringe and/or bend contour contrast was available 5 also aided visualization. This sometimes involved enlarging the perforation to increase wedge angles at the perforation edge, because contrast...