Brigitte Parmentier

In Situ Phosphorus Doping of Germanium by APCVD

Germanium is increasingly being studied for application in advanced nanoelectronic devices, due to its high intrinsic carrier mobility. While broad knowledge and understanding of in-situ doping of Si is available, very little is known on in-situ doping of Ge. Phosphorus has been identified as one of the most promising n-type dopants for Ge, because of its high electrical activity. However, studies of the quality of ion-implanted P-doped Ge layers showed unsatisfactory behavior. A considerable difference between the levels of the electrical solubility and equilibrium solid solubility of P in Ge has been reported. The highest electrically active level of ionimplanted P in Ge reported to date is of 5-6×10 cm. The interest in in-situ doping of Ge was triggered by the possibility of increasing the electrically active levels obtained for n-type dopants at the same time as having better control over the shape of the dopant profile and its location. We present the first results on in-situ P doping of Ge by APCVD.

Advanced carrier depth profiling on Si and Ge with micro four-point probe

In order to reach the ITRS goals for future complementary metal-oxide semiconductor technologies, there is a growing need for the accurate extraction of ultrashallow electrically active dopant (carrier) profiles. In this work, it will be illustrated that this need can be met by the micro four-point probe (M4PP) tool. M4PP sheet resistance measurements taken along beveled Si and Ge blanket shallow structures will be investigated. From the differential sheet resistance changes, the underlying carrier profile can be reconstructed without the need to rely on a complicated contact modeling, i.e., M4PP carrier profiling is an absolute carrier depth profiling technique. On Si, it is found that the more sensitive a structure is to carrier spilling along the bevel, the better the M4PP system performs relative to conventional spreading resistance probe (SRP) due to its much lower probe pressure in combination with its sensitivity to what happens around the probes (and not underneath them). Also for Ge, the same iss...

Photovoltage versus microprobe sheet resistance measurements on ultrashallow structures

Earlier work [T. Clarysse et al., Mater. Sci. Eng., B 114–115, 166 (2004); T. Clarysse et al., Mater. Res. Soc. Symp. Proc. 912, 197 (2006)] has shown that only few contemporary tools are able to measure reliably (within the international technology roadmap for semiconductors specifications) sheet resistances on ultrashallow (sub-50-nm) chemical-vapor-deposited layers [T. Clarysse et al., Mater. Res. Soc. Symp. Proc. 912, 197 (2006)], especially in the presence of medium/highly doped underlying layers (representative for well/halo implants). Here the authors examine more closely the sheet resistance anomalies which have recently been observed between junction photovoltage (JPV) based tools and a micrometer-resolution four-point probe (M4PP) tool on a variety of difficult, state-of-the-art sub-32-nm complementary metal-oxide semiconductor structures (low energy and cluster implants, with/without halo, flash- and laser-based millisecond anneal). Conventional four-point probe tools fail on almost all of thes...