This review is aimed at providing an overview of the technologies of currently-available UVC LEDs, on the challenges that these devices have to face, and on the peculiar features that these modern solid-state emitters exhibit. In particular, this paper is aimed at serving as a bridge between device developers and system manufacturers, by increasing awareness of the differences, both in terms of reliability and operation, that AlGaN-based UVC LEDs show with respect to their visible InGaN/GaN-based counterparts. In this view, this work reports performance and lifetime figures of both commercially-available and research-grade LEDs, showing their limitations in terms of temperature- and current-dependency of the emission spectrum. Both catastrophic and gradual processes that lead to device degradation are discussed, with a particular focus on the kinetics that device properties exhibit during prolonged operation. Moreover, also package-related degradation processes are investigated, which stand-out due to the peculiar structures and materials required to sustain both high-energy UV photons and high localized self-heating, while maximizing the optical efficiency of the LEDs. Ultimately, the data reported within this paper should help the final user in predicting and mitigating degradation effects, while also serving as a reference to manufacturers for the improvement of next generation devices.

Reliability is an essential scientific and technological domain intrinsically linked with system integration. Nowadays, semiconductor industries are confronted with ever-increasing design complexity, dramatically decreasing design margins, increasing chances for and consequences of failures, shortening of product development and qualification time, and increasing difficulties to meet quality, robustness, and reliability requirements. The scientific successes of many micro/nano-related technology developments cannot lead to business success without innovation and breakthroughs in the way that we address reliability through the whole value chain. The aim of reliability is to predict, optimize, and design upfront the reliability of micro/nanoelectronics and systems, an area denoted as “Design for Reliability (DfR)”. While virtual schemes based on numerical simulation are widely used for functional design, they lack a systematic approach when used for reliability assessments. Besides this, lifetime predictions are still based on old standards assuming a constant failure rate behavior. In this chapter, we will present the reliability and failures found in solid-state lighting systems. It includes both degradation and catastrophic failure modes from observation toward a full description of its mechanism obtained by extensive use of acceleration tests using knowledge-based qualification methods.