DEFECT CHARACTERIZATION OF N-TYPE SI1-XGEX AFTER 1.0 KEV HELIUM-ION ETCHING

SiGe heterostructures with their associated geometries and properties promise a novel generation of Si-based devices. Surface processing and , in particular, dry or plasma etching of semiconductors is a key tech nology for producing optoelectronic integrated circuits and high speed electronic devices. We have used deep-level transient spectroscopy (D LTS) in an investigation of the electronic properties of defects intro duced in n-Si1-xGe, (x = 0.00 to 0.25) during 1 keV helium-ion etching (fluence = 1 x 10(12) cm(-2)) prior to the deposition of gold Schottk y barrier diodes (SBDs). Six electron defects (EHe1-EHe6) were detecte d after this processing stage. The defects detected after etching are compared to those introduced by 5.4 MeV alpha-particle (alpha-) irradi ation and, also, radio frequency (rf) sputter-deposition of Au SBDs on material from the same wafer. Four of the electron defects (EHe1, EHe 2, EHe4, and EHe6) are detected in Si. The remaining two defects (EHe3 and EHe5) are only detected in material containing germanium. It was noted that defects introduced during the He-ion etch process have the same DLTS ''signatures'' as defects after the sputter deposition proce ss, but none were the same as those introduced during the alpha-partic le irradiation. The influence of increased Ge content on DLTS peak sha pe and positions is also illustrated and discussed.