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The structure of epitaxially grown layers and the electrical parameters of p–n junctions formed on them
Author(s) -
Pfeifer J.,
Gútai L.,
Haraszthy É. Sz.
Publication year - 1970
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19700050106
Subject(s) - torr , substrate (aquarium) , epitaxy , layer (electronics) , materials science , diffusion , evaporation , germanium , diffraction , etching (microfabrication) , condensation , analytical chemistry (journal) , crystallography , optoelectronics , chemistry , composite material , optics , silicon , oceanography , physics , chromatography , thermodynamics , geology
Germanium layers were evaporated onto p‐type substrates in oil diffusion pumped systems under pressures varying between 3 × 10 −5 and 1 × 10 −8 torr. Evaporation parameters: CP‐4 etched (111) Ge substrate; 810°C substrate temperature; condensation rate: 3–5 μmin −1 ; layer thickness: 15–25 μ. Structural properties were determined by etching rate, microscopy and electron diffraction examinations. Graded p–n junctions were formed by diffusion into the layers. I–V, C–V characteristics of the junctions and storage‐time were determined. Hole concentrations between 1 × 10 18 and 4 × 10 15 cm −3 were found. The lifetime of the minority carriers was found to be 0.1–1 μs, depending on the pressure during evaporation. It is suggested, that the interfaces between layers and substrates possess the worst structural properties and that the electrical properties of p–n junctions are much more characteristic of the layer quality than the results of the proper structural investigations.