Intrinsic and extrinsic diffusion of indium in germanium

Abstract

Diffusion experiments with indium ͑In͒ in germanium ͑Ge͒ were performed in the temperature range between 550 and 900°C. Intrinsic and extrinsic doping levels were achieved by utilizing various implantation doses. Indium concentration profiles were recorded by means of secondary ion mass spectrometry and spreading resistance profiling. The observed concentration independent diffusion profiles are accurately described based on the vacancy mechanism with a singly negatively charged mobile In-vacancy complex. In accord with the experiment, the diffusion model predicts an effective In diffusion coefficient under extrinsic conditions that is a factor of 2 higher than under intrinsic conditions. The temperature dependence of intrinsic In diffusion yields an activation enthalpy of 3.51 eV and confirms earlier results of Dorner et al. ͓Z. Metallk. 73, 325 ͑1982͔͒. The value clearly exceeds the activation enthalpy of Ge self-diffusion and indicates that the attractive interaction between In and a vacancy does not extend to third nearest neighbor sites which confirms recent theoretical calculations. At low temperatures and high doping levels, the In profiles show an extended tail that could reflect an enhanced diffusion at the beginning of the annealing.

Radiation-enhanced self- and boron diffusion in germanium

“…The second term inside the bracket on the right hand side of Eqs. (12) to (15) considers the possible impact of a built-in electric field on the diffusion of charged defects 44 . p(x) is the free hole concentration, which is determined by the concentration of the charged defects via the neutrality equation (10)).…”

“…Numerical solutions of the differential equations (12) to (15) are shown by the solid lines in Figs. 3 and 5.…”

“…In the case of Ge fundamental studies on diffusion clearly reveal the dominance of V in self-and dopant diffusion under thermal equilibrium conditions [6][7][8][9][10] . This, in particular, holds for the diffusion of n-type (phosphorus, arsenic, and antimony) 10 and p-type (aluminium, gallium, indium) [11][12][13][14][15] dopants. No evidence of I has been found in conventional self-diffusion experiments 16 .…”

Isovalent doping and the CiOi defect in germanium

“…Although germanium (Ge) was implemented in the first transistor commencing the solid state electronics era silicon (Si) prevailed for applications in microelectronics, photovoltaics and sensors for many decades due to its high quality crystal growth technology and advantageous native oxide [1][2][3][4][5][6][7][8][9][10][11][12]. In the past few years materials with advantageous physical properties (e.g.…”

“…In the past few years materials with advantageous physical properties (e.g. higher carrier mobilities, low dopant activation temperatures and smaller band-gap) such as germanium (Ge) are becoming increasingly important [1][2][3][4][5][6][7][8][9][10][11][12]. The consideration of alternative substrates is mainly due to the high-k gate dielectric materials, which have effectively eliminated the requirement of a good quality native oxide in advanced nanoelectronic devices [1].…”