FORMATION OF HIGH-MOBILITY SILICON-GERMANIUM STRUCTURES BY LOW-ENERGY PLASMA ENHANCED CHEMICAL VAPOR DEPOSITION

摘要

Method for making semiconductor structures comprising the steps:forming a virtual substrate on a silicon substrate with a graded Si1-xGex layer and a non-graded Si1-xGex layer, using a high-density, low-energy plasma enhanced chemical vapor deposition (LEPECVD) process with a growth rate above 2nm/s, a substrate temperature between 400° and 850° C, and a total reactive gas flow at the gas inlet between 5 sccm and 200 sccm;forming an active region on the virtual substrate that comprises a Ge-channel and at least one modulation-doped layer using a low-density, low-energy plasma enhanced chemical vapor deposition (LEPECVD) process by introducing hydrogen (H2) into the growth chamber, maintaining a substrate temperature between 400° and 500° C, and by introducing a dopant gas in a pulsed manner into the growth chamber to provide for the modulation-doped layer.