Selective growth of B 1-NbN in Nb thin film by high-dose nitrogen molecular ion implantation
- PDF / 462,699 Bytes
- 5 Pages / 593.28 x 841.68 pts Page_size
- 95 Downloads / 140 Views
Masaya Iwaki RIKEN (The Institute ofPhysical and Chemical Research), Hirosawa 2-1, Wako, Saitama-ken 351-01, Japan (Received 1 June 1988; accepted 3 August 1988)
Nitrogen molecular ion implantations have been performed in niobium thin films to form B\NbN layers with an accelerating voltage of 150 kV up to a dose of 5 X 1017 N 2+ ions/cm 2 at room temperature. Measurements of superconducting transition temperature (Tc), Auger electron spectroscopy analyses (AES), and x-ray diffraction analyses (XRD) have been carried out as a function of nitrogen dose in order to characterize the implanted layer. It has been found that there are two regions in the dose dependence of Tc; in the low-dose case, Tc decreases from the initial value of 8 K to less than 4.2 K with increasing dose, and in case of the high dose (more than 2.5 X 1017 ions/cm 2 ) it increases rapidly to 11 K and becomes independent of the implantation dose. The XRD patterns indicate the generation of lattice disorder at the low dose, the formation of Nb 2 N and eNbN at the intermediate dose, and the formation of
Data Loading...
