The objective of this research is to develop an understanding of the trade-offs between performance and reliability in sub 100-nm silicon-on-insulator (SOI) CMOS technologies. Such trade-offs can be used to demonstrate high performance reliable circuits in scaled technologies. Several CMOS reliability concerns such as hot-carrier stress, ionizing irradiation damage, RF stress, temperature effects, and single-event effects are studied. These reliability mechanisms can cause temporary or permanent damage to the semiconductor device and to the circuits using them. Several improvements are made to the device layout and process to achieve optimum performance. Parasitics are shown to play a dominant role in the performance and reliability of sub 100-nm devices. Various techniques are suggested to reduce these parasitics, such as the use of the following: a) optimum device-width, b) optimum gate-finger to gate-finger spacing, c) optimum source/drain metal contact spacing, and d) floating-body/body-contact. The major contributions from this research are summarized as follows: 1) Role of floating-body effects on the performance and reliability of sub 100-nm CMOS-on-SOI technologies is investigated for the first time [1], [2]. It is demonstrated through experimental data and TCAD simulations that floating-body devices have improved RF performance but degraded reliability compared to body-contacted devices. 2) Floating-body effects in a cascode core is studied. Cascode cores are demonstrated to achieve much larger reliability lifetimes than a single device. A variety of cascode topologies are studied to achieve the trade-o s between performance and reliability for high-power applications [2]. 3) The use of body-contact to modulate the performance of devices and single-poledouble- throw (SPDT) switches is studied. The SPDT switch performance is shown to improve with a negative body-bias. 4) The impact of device width on the RF performance and reliability is studied. Larger width devices are shown to have greater degradation, posing challenging questions for RF design in strained-Si technologies [3]. 5) A novel study showing the e ect of source/drain metal contact spacing and gate-finger to gate-finger spacing on the device RF performance is carried out. Further, the impact of above on the hot-carrier, RF stress, and total-dose irradiation tolerance is studied [3], [4]. 6) Latchup phenomenon in CMOS is shown to be possible at cryogenic temperatures (below 50 K), and its consequences are discussed [5]. 7) A time-dependent device degradation model has been developed in technology computer aided design (TCAD) to model reliability in CMOS and SiGe devices. 8) The total-dose irradiation tolerance and hot-carrier reliability of 32-nm CMOSon- SOI technology is reported for the first time. The impact of HfO2 based gate dielectric on the performance and reliability is studied [6]. 9) The impact of technology scaling from 65-nm to 32-nm on the performance and reliability of CMOS technologies is studied [6]. 10) Cryogenic performance and reliability of 45-nm nFETs is investigated. The RF performance improves significantly at 77 K. The hot-carrier device reliability is shown to improve at low temperatures in short-channel CMOS technologies.

Recently, several SiGe HBT devices fabricated on CMOS-compatible silicon on insulator (SOI) substrates (SiGe HBTs-on-SOI) have been demonstrated, combining the well-known SiGe HBT performance with the advantages of SOI substrates. These new devices are especially interesting in the context of extreme environments - highly challenging surroundings that lie outside commercial and even military electronics specifications. However, fabricating HBTs on SOI substrates instead of traditional silicon bulk substrates requires extensive modifications to the structure of the transistors and results in significant trade-offs. The present work investigates, with measurements and TCAD simulations, the performance and reliability of SiGe heterojunction bipolar transistors fabricated on silicon on insulator substrates with respect to operation in extreme environments such as at extremely low or extremely high temperatures or in the presence of radiation (both in terms of total ionizing dose and single effect upset).

Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 73-76). Also available in electronic format on the Internet.

Thesis (M.App.Sc.) - Carleton University, 2007. / Includes bibliographical references (p. 112-118). Also available in electronic format on the Internet.

This dissertation presents the design and development of a mixed-signal low noise second-order integrated circuit (IC) for the open-loop and closed-loop operation of integrated capacitive micro- and nano-gravity accelerometers. The micromechanical accelerometers are fabricated in thick (less than 100 m) silicon-on-insulator (SOI) substrates. The IC provides the 1-bit digital output stream and has the versatility of interfacing sensors with different sensitivities while maintaining minimum power consumption (less than 5 mW) and maximum dynamic range (90 dB). A fully-differential sampled-data scheme is deployed with the ability of low-frequency noise reduction through the use of correlated double sampling (CDS) scheme. In this work, the measured resolution of the closed-loop CMOS-SOI accelerometer system, in the presence of high background accelerations, is in the micro-g (g: gravity) range. In this design, a second-order SC modulator is cascaded with the accelerometer and the front-end amplifier. The accelerometer operates in air and is designed for non-peaking response with a BW-3dB of 500 Hz. A 22 dB improvement in noise and hence dynamic range is achieved with a sampling clock of 40 kHz corresponding to a low oversampling ratio (OSR) of 40. The interface IC consumed a current of 1.5 mA from a supply of 3 V.