Developing semiconductor structures for hardcore optoelectronic devices has always been a challenging job for professionals. In an attempt to make this job less troublesome, a team from the University of Illinois has created a way to chemically entrench sequenced arrays into the semiconductor gallium arsenide.
The aforesaid semiconductor is utilized in solar cells, LEDs, lasers, capacitors, sensors and FETs. Considering that III-V group substances are apparently difficult to dry etch and therefore get damaged easily, the team opted for a metal-assisted chemical etching process (MacEtch). It is a wet-etch method that was initially developed for silicon.
This method accessed a single direction from top to down unlike other wet techniques. It also seemed to be relatively swifter as compared to other dry etch avenues. In the research, the team conditioned the chemical solution and reaction states to work optimally for the III-V semiconductor gallium arsenide (GaAs).
This procedure can be done is 2 steps. Firstly, a slim layer of metal is carved on the GaAs surface after which the semiconductor with the metal pattern is dipped into the MacEtch chemical fluid. As the reaction is catalyzed by the metal, just the portions coming in contact with the metal are etched away. As the etching is done, the metal can be cleared off from the surface without any sort of damage.
“It is a big deal to be able to etch GaAs this way. The realization of high-aspect-ratio III-V nanostructure arrays by wet etching can potentially transform the fabrication of semiconductor lasers where surface grating is currently fabricated by dry etching, which is expensive and causes surface damage,” specified electrical and computer engineering professor Xiuling Li.
For generating metal film patterns, the team accessed a technique known as soft lithography. The team believed that the combo of MacEtch and soft lithiography could be an ideal way to synthesize greater area and high-aspect-ratio III-V nanostructures in a cost-friendly manner.
The research is published in the journal, Nano Letters.