GaN技术杂谈

随着人工智能（AI）、机器人和太空系统重新定义功率电子学的可能性，氮化镓（GaN）技术持续引领这一变革。在最近接受 Electronic Product Design & Test (EPDT) 的采访中，EPC 的首席执行官兼联合创始人 Alex Lidow 博士分享了他对 GaN 如何重塑半导体格局的见解——以及这种快速发展的技术接下来将走向何方。

随着全球对光伏（PV）系统需求的增长，制造商面临在不牺牲可靠性的情况下降低成本的巨大压力。创新技术对于实现这些目标至关重要，特别是对于商业和住宅光伏系统。这些系统通常分为两种主要配置：微型逆变器和串式逆变器。

氮化镓(GaN)是一种全新的使能技术，可实现更高的效率、显着减小系统尺寸、更轻和于应用中取得硅器件无法实现的性能。那么，为什么关于氮化镓半导体仍然有如此多的误解？事实又是怎样的呢？

移动性是所有经济体的驱动力因素。电动出行（或称e-Mobility）是一种清洁且具有影响力的方式，能够在不增加低效电机或燃烧化石燃料发动机对环境压力的情况下保持商业活动的运转。对于高效且紧凑的电机驱动设计需求日益增加。EPC公司正在开发用于电动出行应用的基于GaN的电机驱动参考设计，以启动支持这一趋势的竞争性和环保替代方案。

48 V 正在被许多应用采用，包括 AI 系统、数据中心和轻度混合动力电动车。然而，传统的 12 V 生态系统仍然占主导地位，因此需要高功率密度的 12 V 转 48 V 升压转换器。eGaN® FET 的快速开关速度和低 RDS(on) 可以帮助解决这个问题。 本文评估了一种使用由瑞萨的 ISL81807 控制器 IC 直接驱动的 eGaN FET 的 12 V 转 48 V、500 W DC-DC 功率模块的设计，该模块采用简单且低成本的同步升压拓扑。

介绍：高效电力转换感谢作者和科罗拉多大学博尔德分校 | CUB · 电气、计算机和能源工程系 (ECEE) 的贡献。  

Written by Michael de Rooij and Alana Nakata - Efficient Power Conversion

Published in: PCIM Europe 2017; International Exhibition and Conference for Power Electronics, Intelligent Motion, Renewable Energy and Energy Management; Proceedings of

eGaN FETs, which are available in non-traditional chip scale packages (CSP) as land grid array (LGA) and/or ball grid array (BGA) formats, have repeatedly demonstrated higher power density and higher efficiency performance than equivalent MOSFETs across various applications ^{[1, 2]}. Those improvements are contingent upon proper layout practices documented extensively in ^{[1, 3]} that minimize unwanted parasitic elements. Over the seven years since eGaN FETs were first launched into the market there have been a total of 127 device failures out of a total of more than 17 billion hours in actual use in the field, 75 of which were a result of poor assembly technique or poor printed circuit board (PCB) design practices ^[4]. Designers are becoming more familiar with the PCB design rules that affect manufacturability and are less forgiving compared to MOSFETs due to their relatively smaller sizes. This paper will cover the various guidelines for PCB design that maximize the performance of eGaN FETs and reliability yet still rely on existing PCB manufacturing capabilities.

Gallium nitride (GaN) is a better semiconductor than silicon. There are many crystals that are better than silicon, but the problem has always been that they are far too expensive to be used in every application where silicon is used. But, GaN can be grown as an inexpensive thin layer on top of a standard silicon wafer enabling devices that are faster, smaller, more efficient, and less costly than their aging silicon counterparts.

Televisions can get their content wirelessly, but there is one set of wires they still need: those in their power cord. The consumer electronics industry has floated ideas for freeing TVs from their power cords, but this goal remains elusive. There are several reasons, such as the difficultly of meeting high-power requirements for large-screen TVs and the need for identifying an economical technology. Nevertheless, eGaN FETs could play a role in making TVs truly cordless devices.

The previous installment in this series focused on the physics of failure surrounding thermo-mechanical reliability of EPC eGaN® wafer level chip-scale packages. A fundamental understanding of the potential failure modes under voltage bias is also important. This installment will provide an overview of the physics of failure associated with voltage bias at the gate electrode of gallium nitride (GaN) field effect transistors (FETs). Here we look at the case of taking the gate control voltage to the specified limit and beyond to investigate how eGaN FETs behave over a projected lifetime.