Strain evolution during the silicidation of nanometer-scale SiGe semiconductor devices studied by dark field electron holography

SiGe is routinely used to induce strain in modern semiconductors in order to improve the mobility of the carriers in the channel. Due to the absence of a technique that can accurately measure the strain in these devices with nanometer-scale resolution it has been difficult to assess the effects of processing such as silicidation on the compressive strain in the conduction channel. Here we show that by using dark field electron holography, the strain evolution at various stages of the device processing can be observed, showing that the silicidation process does in fact significantly reduce the strain in the conduction channel.