The current-voltage characteristics of p(++)-InGaAs/n-InP diodes grown by molecular beam epitaxy have been studied. When the substrates are directly radiatively heated during the growth (the so-called In-free mounting), a displacement of the electrical junction towards the n-type InP is observed for high doping ([Be] = 9 x 10(19) cm(-3)). This effect comes from an increased Be diffusion, induced by an anomalous growth temperature increase. The growth temperature set point had to be decreased by 80 degrees C to recover the expected current voltage characteristic. Optical absorption measurements carried out in single p(++)-InGaAs layer have shown the high strength of the inter-valence band absorption, which might be responsible for this significant temperature increase. (c) 2006 Elsevier B.V. All rights reserved.