Investigation of Cu-Ge/Gaas Metal-Semiconductor Interfaces for Low Resistance Ohmic Contacts
- PDF / 2,077,942 Bytes
- 6 Pages / 414.72 x 648 pts Page_size
- 91 Downloads / 188 Views
omposition of the layers was determined from the thickness of the elemental Cu and Ge layers assuming the bulk density of these layers. The crystal structure and microstructure of the layers were examined by transmission electron microscopy (TEM) with 200 kV Topcon 002B electron microscope equipped with Noran energy - dispersive x-ray (EDX) detector with superthin Norvar window which allowed us to analyze low-energy x-ray lines. RESULTS The results on electrical properties of the Cu-Ge alloy contacts including specific contact resistivity and specific bulk resistivity measurements were described elsewhere [1,4,7]. Here we just want to emphasize that pure Cu forms Schottky contact, and the layers with Ge concentration in the range 5 to 40 at.% form ohmic contact on n-type GaAs. The minimum value of a specific contact resistivity, 6.5x10" 7 2.cm 2 , on n-GaAs (lxl017 cm 3 ) was obtained for Cu-Ge alloy contact with 30 at.% of Ge. 5 The n-channel GaAs metal-semiconductor field-effect transistors using the ohmic contacts with 30 at.% of Ge have exhibited a considerably higher extrinsic transconductance (145 mS/mm) compared to the devices with AuGeNi and Ge/Pd contacts [1]. Layers with Ge deficiency to form (-phase (
Data Loading...
