Diffusion and activation of n-type dopants in germanium

The diffusion and activation of $n$-type impurities (P and As) implanted into $p$-type Ge(100) substrates were examined under various dose and annealing conditions. The secondary ion mass spectrometry profiles of chemical concentrations indicated the existence of a sufficiently high number of impurities with increasing implanted doses. However, spreading resistance probe profiles of electrical concentrations showed electrical concentration saturation in spite of increasing doses and indicated poor activation of As relative to P in Ge. The relationships between the chemical and electrical concentrations of P in Ge and Si were calculated, taking into account the effect of incomplete ionization. The results indicated that the activation of P was almost the same in Ge and Si. The activation ratios obtained experimentally were similar to the calculated values, implying insufficient degeneration of Ge. The profiles of P in Ge substrates with and without damage generated by Ge ion implantation were compared, and it was clarified that the damage that may compensate the activated $n$-type dopants has no relationship with the activation of P in Ge.Comment: 6 pages, 4 figure

effect of urban geometric condition on Drag force coefficient of urban surface

Drag force coefficient (Cd) of various types of urban-like roughness was measured in a wind tunnel. The geometry of roughness used for measurement was determined to clarify the effects of arrangement pattern, packing density and variation of roughness height. The result indicates that the nonuniformity of roughness height increases not only Cd but also roughness length z0. This tendency is more obvious under the condition of high packing density

都市表面抵抗係数に及ぼす幾何形状の影

Drag force coefficient (Cd) of various types of urban-like roughness was measured in a wind tunnel. The geometry of roughness used for measurement was determined to clarify the effects of arrangement pattern, packing density and variation of roughness height. The result indicates that the nonuniformity of roughness height increases not only Cd but also roughness length z0. This tendency is more obvious under the condition of high packing density