Article

Residual doping concentration estimation in a separation by IMplanted OXygen film using current measurements

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Abstract

In situ measurements of static characteristics for an ad-hoc silicon-on-insulator (SOI) device represent an important method for SOI technologies characterisation. The Separation by IMplanted OXygen (SIMOX) technique is based on oxygen ions implantation into Si-film. After annealing, an increased doping concentration was reported, because of the residual oxygen clusters within the film, giving rise to oxygen thermal donors. Therefore this study offers an original algorithm for doping concentration estimation in these SOI films. A specific device used for in situ electrical characterisation of SOI wafers is the pseudo-metal oxide semiconductor (MOS) transistor. In this study, the doping concentrations extraction is based on graphical solution of a non-linear equation and third-order derivative zeroing of the measured static characteristics. In this scope, experimental curves ID-VG, in inversion and accumulation were experimentally measured for a pseudo-MOS transistor made in SIMOX technology. In this situation, the threshold and flat-band voltage are extracted, free of classical conventions. The extracted doping concentration in film is roughly 5.8 × 1015 cm- 3; also the conductivity is changed from p to n in film, as the literature predicted.

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... The ITO electrode has been used as Gate contact. This configuration (Fig. 5a) that contains two probes onto the active layer has been also involved in the pseudo-Metal-Oxide-Semiconductor (pseudo-MOS) transistor [34][35][36] or OTFT with bottom gate top contacts (BGTC) [37]. Three films of PABA-NCS material with different thickness values of 200, 400 and 600 nm has been deposited on the same substrate previously covered by 100 nm polystyrene (Fig. 5b). ...
... Hence, the regime at positive gate voltage has to be assigned to the depletion regime that corresponds to each PABA-NCS film thickness of 200, 400, or 600 nm. Similar characteristics of the pseudo-MOS transistors with Si-films, were previously reported [35][36][37]. ...
... An important discussion envisages a comparison among the static characteristics of our fabricated PABA-NCS organic transistor, the I D -V GS curves of an experimental transistor with pentacene [41] and some experimental picked points of a similar pseudo-MOS transistor with 200 nm Sin-type film on 400 nm SiO 2 [35]. To emphasize some novel aspects, the transfer characteristics are compared at logarithmic scale for current (Fig. 8). ...
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... The Fe3O4-SSA film was contacted by two probes, i.e., the source and drain, and the ITO film was contacted by a third probe, i.e., the gate. This point-contact transistor, also named pseudo-MOS (Metal Oxide Semiconductor) or Ψ-MOSFET (Metal Oxide Semiconductor Field Effect Transistor)transistor, is specifically used for the in-situ electrical characterization of the conduction in thin semiconductors on insulators [17,18], including organic biomaterials [19,20]. The next paragraph presents the synthesis and microphysical characterization of Fe3O4-SSA. ...
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... The carrier concentrations of a-IGZO layers or SOI films are usually obtained by Hall measurements or current measurements [19]- [23]. However, these techniques are difficult to be applied to exactly measure the carrier concentrations in S/D contact regions and/or a patterned a-IGZO layer in a fabricated TFT. ...
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The pseudo-MOS transistor (Ψ-MOSFET) is a surprising and useful technique for the rapid evaluation of SOI wafers, prior to any CMOS processing. We review the static and dynamic modes of operation as well as the main models and methods for electrical parameter extraction. Selected numerical simulations are presented in order to clarify the optimal conditions of operation. Finally, practical applications are exemplified which illustrate the efficiency of the Ψ-MOSFET technique for in situ characterization of SOI technologies and processes
Non-linear electrical conduction in semiconductor structures
  • A Rusu
Rusu, A.: 'Non-linear electrical conduction in semiconductor structures' (Bucharest House Publishing of the Romanian Academy, Romania, 2000)