Analogue integrated circuit design started with primitive transistor models that were able to capture the operation of solid-state devices. Only simple functionality could be accomplished through the circuits designed. Via aggressive scaling, however, the number of transistors that could be integrated has dramatically increased, thereby boosting the capability of circuits to achieve diverse and complex tasks. At first, more transistors meant an augmented computational cost only, since a large number of equations had to be solved concurrently to determine the circuit response. The time to find out the transistor operating points became crucial. Transistor models should be both accurate and easy to evaluate. Thus, alternative approaches have been proposed to characterize the device physics mathematically, some of which have led to the development of well-known transistor models, such as BSIM, EKV, and PSP, over the years. As the scaling continued in its unprecedented pace, novel modelling issues started to arise. Simulations using primitive device models with few parameters were not sufficient to predict the outcomes of measurements. There were different reasons for this observation: smaller transistor sizes were triggering quantum mechanical effects, such as quantum tunnelling as well as entailing models with more complex underlying equations. Moreover, with shorter geometries, device-todevice variation of transistor parameters significantly increased. There was a need to characterize the changes induced by manufacturing steps with a separate set of parameters. Finally, devices were failing after prolonged usage due to the high vertical and lateral electric fields they undergo during regular operation. These were basically reliability issues occurring towards the end of the device lifetime. Thus, reliability phenomena needed to be described with dedicated models, as well.

Chapter Contents:

• Conclusion

Inspec keywords: electric fields; integrated circuit design; integrated circuit modelling; microwave devices; transistor circuits; integrated circuit reliability; integrated circuit manufacture; analogue integrated circuits

Other keywords: entailing models; aggressive scaling; device-to-device variation; vertical electric fields; solid-state devices; reliability issues; analogue integrated circuit design; circuit response; quantum tunnelling; augmented computational cost; lateral electric fields; PSP; transistor operating points; circuit manufacturing steps; quantum mechanical effects; transistor models; EKV; BSIM

Subjects: Reliability; Microwave circuits and devices; Analogue circuit design, modelling and testing; Production facilities and engineering; General electrical engineering topics; Semiconductor integrated circuit design, layout, modelling and testing