Electronic properties of defects introduced in p-type Si1−xGex during ion etching

We have investigated the electronic properties of defects introduced in boron-doped, strained p-type Si1−xGex (x=0–0.15) during 0.75-keV argon Ar-ion etching, by deep level transient spectroscopy. These defects are compared to those introduced during e-beam deposition of metal contacts and after 5.4-MeV alpha-particle irradiation. Defect HAr1d, detected in p-Si, has similar electronic properties as He2 and Ha15 detected after electron and alpha-particle irradiation, respectively. The variation in activation energy of HAr1d with Ge fraction was studied, and it was found to follow the same change as the band gap of strained Si1−xGex. This defect has a concentration, which decreases sharply from the metal–semiconductor surface. It also has an activation energy, which depends on the Ge content and is pinned to the conduction band.