Reactive ion-beam etching smooths indium-based semiconductor surfaces

Reactive ion-beam etching smooths indium-based semiconductor surfaces

Researchers at the Institute for Surface Modification (Leipzig, Germany) have used reactive ion-beam etching with nitrogen to smooth out surface roughness in three indium-containing III-V semiconductors (InP, InAs, and InSb) used in electronic and optoelectronic devices. The argon-ion beam-etching method used for gallium-based semiconductors has not proven as successful in producing smooth surfaces in indium-containing semiconductors, according to the researchers.

In the experiment, samples of InP, InAs, and InSb were initially prepared using the argon-ion beam-etching method, and surface roughness was measured using atomic force microscopy. Root-mean-square roughness values obtained were 36.5 ۮ.5 nm for InSb, 3.3 ۫.1 nm for InP, and 2.8 ۪.1 nm for indium arsenide. Reactive ion-beam etching with nitrogen reduced root-mean-square surface roughnesses to 1.4 ۪.1 nm, 0.8 ۪.1 nm, and 0.2 ۪.1 nm, respectively. The researchers found that the smoothing became increasingly effective with increasing ion dose at ion beam angles of incidence greater than 70° and approaching the normal. Changes in ion-beam energy had little effect on smoothing of InSb and InAs surfaces. Smoothing of In¥was more effective when ion-beam energy was reduced from 500 to 200 eV, however.