Si- and Mg-implanted InP,GaInAs and short-time proximity cap annealing

Si- and Mg-ions with energies of 180 keV have been implanted into semi-insulating InP substrates and low doped n- and p-type GalnAs epitaxial layers (3 · l0¹⁶cm⁻³). Sheet resistances and doping profiles are analyzed and compared with LSS theory. Post-implantation annealing is studied with respect to encapsulation, time and temperature. We have tested as new encapsulation techniques for InP the simple proximity cap annealing and for GalnAs the As-doped spun-on SiO₂. Proximity cap annealing yields decomposition-free surfaces when using a recessed capsubstrate. At annealing temperatures of around 800 °C less activation is obtained than with conventional PSG annealing and a surface accumulation of charge-carriers is established. A time limit of around 3 min is found for Si- and Mg-implanted InP, beyond which the sheet resistance no longer decreases and the doping saturates. For Si in InP, short-time annealing yields to a 68 % activation of carriers, not significantly higher than with conventional long-time annealing. In the case of Si in GalnAs, however, short-time annealing is much more effective. A 100 % activation is obtained for a dose of 2.10¹⁴ cm⁻², while only 7 % is found for long annealing. Even at such a high dose of 1. 10¹⁶cm⁻² we have achieved about an order of magnitude higher activation with short annealing than with long annealing. Most information contained in this paper was presented at the 1984 Electron Materials Conference as paper L-l.