Semiconductor nanostructures defined by self-organizing polymers

摘要

In the nearfuture it will be more and more important to produce real nanometer-sized structures for semiconductor devices (e.g,quantum dot lasers) but also for nano-biomechanical applications like the so-called 'total analysis system" implemented on one chip.We describe here a technique to create nanometer-sized structures in semiconductors and metals by the use of self-assembling diblock copolymers as nano-lithographic masks.Semiconductor quantum structures ith very high aspect ratio of 1:10 were fabricated from III-V semiconductor heterostructures by anisotrpic dry etching.In a first step,so-called diblock copolymer micelles were generated in a toluene solution.These micelles were loaded by a noble-metal salt.With a "Langmuir Blodgett" technique we can decorate complete wafers with a monolayer of highly ordered micelles,covering almost the complete surface.After treatment in a hydrogen plasma all of the organic components are removed and only crystalline metal clusters of approx=12 nm size remain.This metal cluster mask can be used directly in a highly anisotropic chlorine dry etching process to etch cylinders in GaAs and its In and Al alloys.It is also possible to etch through a quantum well layer underneath the surface in order to produce quantum dots.By evaporating metals and applying a wet chemical image reversal process,we can invert the etched structure and generate a gauzy gold film with nano-holesinside.It is thinkable touse this porous gold film as a nano-filter in upcoming nano-biotechnology applications.