Mask-edge effects at low ion implantation energies for cluster covered silicon

• Published in: Physica. B, Condensed matter Condensed matter, 1999-06, Vol.266 (4), p.345-355
• Main Authors: Hul'ko, O.V, Danailov, D, Karpuzov, D, Zinke-Allmang, M
• Format: Article
• Language: English
• Subjects: Applied sciences; Clusters; Electronics; Exact sciences and technology; Lithography, masks and pattern transfer; Mask-edge effects; Microelectronic fabrication (materials and surfaces technology); Selective etching; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Surface patterning
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/S0921-4526(99)00041-1

Clusters of independently tailored areal density and size distribution were grown on semiconductor surfaces by molecular beam epitaxy and were used subsequently as masks for selective ion beam modification. Field emission scanning electron microscopy shows sharp interfaces between the amorphous area exposed to ion beams and areas of crystalline silicon covered by clusters. Partial etching of the substrate leads to narrow trenches around the initial cluster site, suggesting significantly enhanced etching near the amorphous-crystalline interface. The results are explained on the basis of a slight density variation in the substrate near the cluster periphery due to a break in symmetry of the recoil atom incorporation. Computer simulations were carried out to further characterize these results, using a program based on the well-established TRIM code to model atomic collision cascades in a matrix. The resulting density distributions correlate well with the experimentally observed wet etching patterns, strongly suggesting a relation between cluster-masking related density variations in the amorphized silicon and the etching rate.