Thèse de doctorat en Informatique
Sous la direction de Jean-Marc Delosme.
Soutenue en 2005
Deep sub-micron CMOS technologies allow a very good integration of mocroelectronics circuits, as well as an increase of the implemented functions and speed of computations. At the same time, the problems created by parasitic effects and process fluctuations are an issue to be taken into consideration. New CMOS processes have been developed such as triple-well and silicon-on-insulator (SOI); they offer the freedom to isolate functional blocks in integrated circuits in separate islands, and therefore to have better control of the power consumption and of the circuit performance. Due to these technologies it is possible to tune some intrinsic parameters of the transistors, like threshold voltage or leakage current, by controlling the bulk/body of MOS transistors. A method for the threshold voltage control in deep-submicron triple-well 120 nm CMOS technology is described in this work; this process gives full access to the bulk of both transistors tyupes, NMOS and PMOS. This method can also be used for circuits implemented in PD-SOI processes. Two functionnal blocks, an operational amplifier and a threshold voltage mismatch VT monitor, have been developed for this application. This tchnique of threshold voltage control by body-biasing can be also used to diminish the parasitic effects caused by technology fluctuations on transistor parameters. RF circuits represent the second subjects of this research. Two frequency dividers have been realized in silicon-on-insulator (SOI) and bulk 90 nm CMOS; they reach an input frequency of 34 GHz and are supplied from a 1 V voltage source. Using the same method of VT control by body-biasing the circuit input sensitivity and the maximum input frequency can be tuned. The same approach has been applied in the case if a high-frequency quadrature voltage-controlled oscillator (VCO) where the transistor bulk is used as an external input for changing not only the transistors threshold voltage but also the oscillation frequency.
Mixed-signal design for portable communication at low-voltage and high-frequency in CMOS bulk and SOI
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