Transmission electron microscopy study of two-dimensional dopant profiling in metal-oxide-semiconductor field effect transistor test structures and devices

Transmission electron microscopy (TEM) combined with selective chemical etching was used to assess two-dimensional dopant profiles in the metal-oxide-semiconductor field effect transistor (MOSFET) test structures with a gate length of approx. 1 μm and real MOS devices with gate lengths of 500 and 80 nm. It is shown that the chemically delineated junction depth increases gradually with increasing implantation energy and dose. The TEM results show that crystallographic defects hamper the doping-dependent etching process in the n-type semiconductor. The lateral dopant profiles simulated by SUPREM IV are compared with TEM results calibrated by secondary ion mass spectroscopy. The delineation technique is effectively applied to characterize MOS devices.