Trench technique
The trench technology ( English trench , trench ' ) is a semiconductor fabrication process, in particular in the production of DRAM is used. The central element of this technology is the trench or hole capacitor .
description
.svg)
The trenches used in trench technology are etched into the silicon crystal by reactive ion etching , then coated on the inside with a dielectric and an electrically conductive material, so that a capacitor is created. The resulting trenches can have an aspect ratio (ratio of depth to opening diameter) of up to 70: 1 (deep trench; status 2004). This enables a sufficiently large surface for the storage capacitor for DRAM cells and thus the necessary capacities to be achieved with little space requirement.
One possible application for such trench capacitors is their use as storage capacitors in DRAM cells. Since the precise production of deep trenches / holes and the coating of the inside is very complicated, none of the larger memory manufacturers uses them today (2009). Instead, they use what is known as stack technology , in which the storage capacitor is built up above, i.e. in applied layers. The last major manufacturer with trench technology was Qimonda , who also switched to a stack capacitor in 2008 with the development of the buried wordline technology.
In BCD technology , deep trenches are used to contact the substrate material from the front and to electrically isolate components / assemblies from one another in the area of the deep wells. They meet thus a function similar to the shallow trenches in planar CMOS circuits and it also as deep in the style grave insulation ( deep trench isolation called).
Individual evidence
- ↑ Karin Braeckle: Infineon presents breakthrough in DRAM trench technology . On: innovations-report. December 14, 2004
- ↑ Qimonda (Ed.): Buried Wordline . On: Qimonda website. Retrieved February 7, 2009