Picosun Group, Espoo, Finland, reports record performance of silicon-integrated, three-dimensional deep trench microcapacitors manufactured by its ALD equipment, which deposited film stacks of conductive TiN and insulating dielectric Al2O3 and HfAlO3 layers into high aspect-ratio (up to 100) trenches etched into silicon. Up to 1 µF/mm2 areal capacitance was achieved, a new record for this capacitor type.
Power and energy densities were also excellent at 566 W/cm2 and 1.7 µWh/cm2, surpassing the values achieved with most other capacitor technologies. The ALD microcapacitors also showed outstanding voltage and temperature stability, up to 16 V and 100 degrees C, over 100 hours of continuous operation.
“We exploited the room available on the bottom of silicon wafers, of which only a few micrometers of silicon are used for electronic components in integrated circuits, to fabricate silicon-integrated 3D microcapacitors with unprecedented areal capacitance.
“The electrochemical micromachining technology, developed at the University of Pisa over the past decade, enabled etching of high-density trenches with aspect ratios up to 100 in silicon, a value otherwise not achievable with deep reactive ion etching. This became the basis for increasing the areal capacitance of our 3D microcapacitors upon conformal coating with an ALD metal-insulator-metal stack,” says Prof. Giuseppe Barillaro, group leader in the Information Engineering Department at the University of Pisa, Italy.
