Issue link: https://resources.mouser.com/i/1490195
Apex 2022 9 Thermal Failures: Unexpected Behavior One reason thermal generation causes unreliability in analog power electronics is the unexpected behavior it can induce in analog circuits. At their core, analog electronics are composed of components inherently susceptible to changes in their environment. The most fundamental component in analog electronics, the transistor, displays variations in device parameters and behaviors relating directly to its temperature. For example, in metal-oxide- semiconductor field-effect transistors (MOSFETs), key device parameters—such as threshold voltage, carrier mobility, and saturation velocity—all fluctuate based on device temperature. Most analog circuits are fine-tuned to reliably operate based on the transistor's parameters in well-understood and expected conditions. While the performance of analog systems is tested at edge cases, the increasing power density of modern-day devices is causing temperatures to reach new heights, and device performance can degrade accordingly. In the context of an entire analog circuit or subsystem, which is composed of hundreds of transistors, the unexpected behavior of each individual device can accumulate and cascade into larger errors that significantly degrade performance for the circuit as a whole. Thermal Failures: Device Wear and Failure Beyond unreliability during operation, thermal generation can cause unreliability with respect to device lifetime. To better understand this concept, we must first consider the composition of an integrated circuit. Looking top- down at the stack-up of an analog power device, one can usually find a metal housing or case around the device on the top, followed by a power die. The power die is soldered to the device substrate, on top of which lives the physical device components. These components are connected to other components via metal traces and/or bond wires. The substrate itself is then solder-connected to a thick base plate, which provides mechanical rigidity and completes the enclosure. Thermal generation is one of the most significant limiting factors towards achieving high-reliability power electronics design. Apex Microtechnology uses unique device stack-ups and materials to help manage thermals and ensure high-reliability products.