Based on the hydrodynamics energy transport model. the influence of geometrical structure parameters on the hot-carrier-effect immunity in deep-sub-micron grooved gate PMOSFET's is studied. The study results are explained based mechanism. The Structure parameters investigated include the effective channel length, on the device's interior physical the concave corner and the negative junction depth induced by changing the sopurce/drain junction depth or groove depth. The research results indicate that the hot-carrier effect is depressed deeply for grooved gate PMOSFET's even in deep and super-deep-sub-micron regions. and with the increase of the concave corner and the negative junction depth. the hot-carrier-effect immunity becomes better. Those are mainly because that the structure parameters influence the distribution of the electric field in the devices, which influence the ''corner effect" and the transportation of the carriers. (C) 2002 Elsevier Science Ltd. All rights reserved.