Imec为提高GaN性能和实现真正的GaN-IC技术铺平道路

Imec展示GaN半桥与驱动器的完全单片共同集成

比利时鲁汶，2019年5月7 – 今天，在年度科技活动Futuresummits 2019上，世界领先的纳米电子和数字技术研究与创新中心imec宣布，展出一款与驱动器单片集成的功能性GaN半桥。该芯片安装在降压-转换器测试板上，输入电压为48V，输出电压为1V，脉冲宽度调制信号为1MHz。该成果利用了imec的GaN-on-SOI和GaN-on-QST®技术平台，降低了寄生电感并提高了换向速度。

Today, GaN power electronics are dominated by off-the-shelf discrete components.  Half-bridges –common subcircuits in power systems – are fabricated by separate discrete components, either in separate packages, or integrated in one package, especially for the higher voltage ranges.  Realizing half-bridges on chip by using GaN-on-Si technology, is very challenging, especially at high voltages. This is because half-bridges designed on GaN-on-Si technology are limited in performance by a back-gating effect that negatively affects the high-side switch of the half-bridge, and switching noise that disturbs the control circuits.

To unlock the full potential of GaN power technology, imec monolithically co-integrated a half-bridge and drivers in one GaN-IC chip. Complemented by low voltage logic transistors, a suite of passive components for low-ohmic and high-ohmic resistors, and a MIM-capacitor, high-end integrated power systems can be realized on one single die. 

Imec’s solution builds on imec’s GaN-on-SOI and GaN-on-QST® technology platforms that allow for a galvanic isolation of the power devices, drivers and control logic, by the buried oxide and oxide-filled deep trench isolation.  This isolation scheme not only eliminates the detrimental back-gating effect that negatively affects the high-side switch of the half-bridge, but also reduces the switching noise that disturbs the control circuits. With the design of a co-integrated level shifter for driving the high-side switch, a dead-time controller to avoid overlapping gate input waveforms, and an on-chip pulse-width modulation circuit, highly integrated buck and boost convertors can be fabricated.

“Someone might think that by using SOI or QST® wafers instead of Si wafers will result in more expensive technology. However, with GaN-on-Si several discrete devices need to be individually packaged (with advanced packages to take advance of the GaN fast switching performance) and connected to their drivers and other elements at the board or packaged level”, stated Denis Marcon, business development manager at imec. “Instead, with imec’s GaN-IC technology, the full converter including drivers and analog blocks etc. is on-chip, which can then be packaged with simple package technology (as the frequency sensitive components are already connected on-chip). This dramatically saves on the cost of the final power system.”

To further boost the performance of these monolithic integrated power systems, imec aims to extend its platform with additional co-integrated components, such as Schottky diodes and depletion-mode HEMTs. 

“With the aim to further foster innovation in the GaN power electronics, this GaN-IC platform is available for prototyping through our multi-project-wafer (MPW) service”, commented Stefaan Decoutere, program director GaN power electronics at imec.  “The possibilities for high-end power systems with unprecedented performance, either in switching speed, operating frequency or energy efficiency, with reduced inductive parasitics and unseen reduction of the form-factors, will further boost the use of GaN for power supplies in the consumer and re-useable energy market segments.”