Segregation of gold to the silicon (111) surface observed by Auger emission spectroscopy and by LEED

Abstract

A silicon crystal implanted with gold was heated to successively higher temperatures, reaching a maximum of 1250°C, and its surface examined by Auger emission spectroscopy (AES) and LEED at each stage. No recrystallization was observed until the crystal had been heated to 740°C, at which point the AES analysis could be interpreted in terms of the appearance of gold atoms at the surface. At 810°C the Auger peaks from gold were considerably larger than those from silicon, but decreased progressively thereafter as the temperature was raised until, at over 1000°C, the differential distribution was indistinguishable from that of clean silicon. The first LEED pattern observed, at 740°C, was not the Si(111)-7 pattern, but another familiar one, the Si(111)-(radical3 × radical3)-R30° pattern. With increasing temperature, the fraction one-third-order pattern spread over the whole surface and, above 900°C, was joined by another, a fraction one-fifth-order pattern, probably based on a domain structure. At the highest temperature no fractional orders were visible, only a Si (111)-(1 × 1) pattern, with good spot-to-background contrast. The normal 7-pattern could only be achieved by ion bombardment and annealing, not by heat treatment alone, suggesting that there was still a very high density of dislocations remaining from the implantation.

The initial growth of vapour deposited gold films

“…Above this thickness gold particles nucleated to give the Stranski-Krastanov growth mode. The observed mixing of gold and silicon at the interface is in agreement with Barlier work from which it was concluded that gold atoms diffused through single crystals of silicon (10). The reverse situation -diffusion of silicon atoms through gold films -was observed by Hiraki et al (11 to 14).…”

Identification of the Au Coverage and Structure of theAu/Si(111)−(5×2)Surface

“…Bc, 73.20.At, 81.07.Vb The Au/Si(111)-5×2 surface is a representative selforganized one-dimensional (1D) metal chain system [1][2][3][4] and has served as a rich source of intriguing 1D phenomena such as atomic-scale Schottky barriers [5], 1D domain-wall hoppings [6], and confined doping on a metallic chain [7]. Its atomic structure, however, is not yet solved in spite of extensive experimental studies [8][9][10][11][12][13][14][15][16][17][18][19] and density functional theory (DFT) calculations [20][21][22][23][24][25]. This long-standing surface science problem is thus considered a touchstone of our ability to look into the structure of complex surface/nano systems at truly atomic scale.…”

“…Its atomic structure, however, is not yet solved in spite of extensive experimental studies [8][9][10][11][12][13][14][15][16][17][18][19] and density functional theory (DFT) calculations [20][21][22][23][24][25]. This long-standing surface science problem is thus considered a touchstone of our ability to look into the structure of complex surface/nano systems at truly atomic scale.…”

Identification of the Structure Model of theSi(111)−(5×2)−AuSurface

“…Among them, the Sið111Þ-ð5 × 2Þ-Au surface is the oldest structure, discovered about a half century ago [6]. The surface and its relatives, gold atomic chains on Si(111) vicinal surfaces [7,8], have been widely studied for finding and understanding the physics peculiar to quasi-one-dimensional metals [8][9][10][11].…”