Luminescence and microstructure of Er/O co-doped Si structures grown by MBE using Er and SiO evaporation

• Published in: Materials science in semiconductor processing 2000-10, Vol.3 (5), p.523-528
• Main Authors: Duteil, F, Du, C.-X, Joelsson, K.B, Persson, P.O.A, Hultman, L, Pozina, G, Ni, W.-X, Hansson, G.V
• Format: Article
• Language: English
• Subjects: Doping; Electroluminescence; Erbium; Oxygen; Photoluminescence; Si-MBE; TECHNOLOGY; TEKNIKVETENSKAP
• ISSN: 1369-8001; 1873-4081; 1873-4081
• DOI: 10.1016/S1369-8001(00)00075-5

Er and O co-doped Si structures have been prepared using molecular-beam epitaxy (MBE) with fluxes of Er and O obtained from Er and silicon monoxide (SiO) evaporation in high-temperature cells. The incorporation of Er and O has been studied for concentrations of up to 2×10 20 and 1×10 21 cm −3, respectively. Surface segregation of Er can take place, but with O co-doping the segregation is suppressed and Er-doped layers without any indication of surface segregation can be prepared. Si 1− x Ge x and Si 1− y C y layers doped with Er/O during growth at different substrate temperatures show more defects than corresponding Si layers. Strong emission at 1.54 μm associated with the intra-4f transition of Er 3+ ions is observed in electroluminescence (EL) at room temperature in reverse-biased p–i–n-junctions. To optimize the EL intensity we have varied the Er/O ratio and the temperature during growth of the Er/O-doped layer. Using an Er-concentration of around 1×10 20 cm −3 we find that Er/O ratios of 1 : 2 or 1 : 4 give higher intensity than 1 : 1 while the stability with respect to breakdown is reduced for the highest used O concentrations. For increasing growth temperatures in the range 400–575°C there is an increase in the EL intensity. A positive effect of post-annealing on the photoluminescence intensity has also been observed.