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Growth modes and surface reconstructions in the systems of Group I–V and transition metals of the Periodic Table on Si(100) have been studied by scanning tunneling microscopy (STM) as a function of coverage and substrate temperature. The adsorption sites of metal, formation of superstructures and growth mode as functions of coverage and temperature are classified briefly depending on the type of metal. The mechanisms of epitaxial growth and reconstruction are discussed based on the phase diagrams of these systems.

Complex growth and reconstructions of Ag on Si(001)(2 × 1) were studied by STM, LEED, AES and SEM. We find that Ag is first adsorbed at the silicon SB step edge and preferentially forms dimers on the Si terraces. At room temperature Ag grows in a pseudo Stranski-Krastanov (SK) mode. The first layer is not homogeneous and does not cover the substrate completely. In this layer several different structures coexist (e.g. (2 × 2), c(4 × 2), depending on the Ag induced buckling of the Si dimer rows). During the formation of the inhomogeneous layer, three-dimensional islands grow with the orientation Ag(111)//Si(001). At a substrate temperature of 770 K real SK growth is observed and the first layer is homogeneous. This layer has a (2 × 3) structure. On the top of this (2 × 3) layer, Ag islands grow with Ag(001)//Si(001).

Nucleation and growth of Ag on Si(001)(2 × 1) has been studied at tempertures of (300 ÷ 550) K, using intrinsic stress measurement together with several structural methods. Microstructure, growth mode and related intrinsic stress are strongly influenced by the Si(001) dopant concentration. On low p-doped Si(001)(2 × 1) film growth proceeds by Volmer-Weber mode resulting in polycrystalline films at (300 ÷ 400) K and high-quality epitaxial Ag(001) films at (450 ÷ 550) K. On highly doped substrates, on the other hand, epitaxial Ag(111) films grow via Stranski-Krastanov mode at 300 K, indicating the crucial effect of surface dopants on the initial stages of Ag nucleation.

It is well known that thin films develop large intrinsic stress during their preparation. The stress originates from strained regions either within the thin films (grain boundaries, dislocations, voids, impurities) or at the film/substrate interface (lattice mismatch, different thermal expansion) or due to dynamical (recrystallization, interdiffusion) or gas adsorption processes. Since the magnitude of most of these stress contributions is directly correlated with film morphology as well as film growth, important structural information can be extracted from the intrinsic stress. Recent results on various epitaxial thin film systems growing via Volmer–Weber Ag/mica(001), Cu/mica(001), (Ag/Si(001)), Stranski–Krastanov (Ag/Si(001), Ge/Si(001)), and Frank–Van der Merwe modes (Si/Si(001), Fe/MgO(001)) are reviewed.

Growth and microstructure of thin Ag, Cu, and Au films ultrahigh vacuum deposited onto single‐crystalline mica(001) have been studied in situ by intrinsic stress measurements (ISM) and low‐energy electron diffraction. Depending on the respective substrate temperature, three different modes of Vollmer–Weber (VW) growth can be clearly distinguished by ISM: (i) VW‐type nucleation and subsequent columnar grain growth at low temperatures (110 K) where grain‐boundary relaxation is the prevailing stress contribution, (ii) polycrystalline VW mode in a medium temperature range that is characterized by VW‐type nucleation and grain growth in the continuous film and dominated by the capillarity stress, and (iii) epitaxial VW growth mode at temperatures above 470 K for Ag and 600 K for Cu and Au; here a novel stress mechanism due to the formation of ‘‘single‐crystalline grain boundaries’’ appears during the network stage.

Thin films of the noble metals Ag and Au are prospective candidates for application as electrical contacts in high temperature superconductor (HTSC) thin film devices. We present first results on intrinsic stress in Ag and Au films measured during and after their UHV deposition onto YBa2Cu3O7−x thin film substrates. At 110 K film growth proceeds by columnar grain growth with tensile stresses as huge as the tensile strength of the bulk phase. At room temperature and up to 600 K the films grow via island growth developing much smaller film stress. At temperatures above 550 K a compressive stress contribution due to interdiffusion of oxygen from the HTSC substrates into the contact films is observed.

Thin films of Ag, Cu and Au have been deposited onto single-crystalline mica (001) at different substrate temperatures and characterized in uhv by intrinsic stress measurements and low energy electron diffraction, as well as by scanning tunnelling microscopy in air. At room temperature the films are polycrystalline and exhibit film forces that are typical of the polycrystalline Vollmer-Weber mode, i.e. tensile forces during island, network and channel stages of film growth and compressive forces in the continuous films. At temperatures between 500 and 700 K film growth proceeds by the epitaxial Vollmer-Weber mode and films consisting of large, atomically flat grains are obtained. A huge stress contribution due to the formation of single-crystalline domain walls is observed during the network stage.

The influence of oxygen on the growth and microstructure of thin iron and nickel films has been investigated with intrinsic stress measurement. Under the best uhv conditions iron grows via columnar grain growth exhibiting only tensile stress, while nickel shows the more complex stress behaviour of pronounced island growth. In the latter case oxygen causes a gradual transformation to the columnar grain growth mode at an oxygen partial pressure of 1 × 10−8 hPa. In the columnar grain growth regime of both metals oxygen incorporation leads to a compressive stress contribution. A further increase of the oxygen partial pressure leads to the formation of the respective oxide films.

Growth and microstructure of UHV‐deposited thin films of Fe and Ni−two metals used in magnetic storage technology−have been investigated with intrinsic stress measurement. Fe exhibits tensile film forces typical of columnar grain growth. At oxygen partial pressure higher than 5×10−9 hPa the films incorporate oxygen leading to an increasing compressive stress contribution; at 2×10−7 hPa a magnetic oxide film is deposited. Ni exhibits film forces characteristic of pronounced island growth which gradually transform to the ones indicating columnar grain growth at oxygen pressures above 1×10−9 hPa; at 1×10−6 hPa a transparent oxide film is deposited.

The growth of Ag on 4\ifmmode^\circ\else\textdegree\fi{}-misoriented, single-domain Si(001) surfaces at 130 K yields continuous and epitaxial overlayers with a (111) orientation. The close-packed rows of Ag atoms are parallel to the (2\ifmmode\times\else\texttimes\fi{}1) dimer rows and run perpendicular to the step edges. The dimer orientation can be rotated by 90\ifmmode^\circ\else\textdegree\fi{} by inducing a (3\ifmmode\times\else\texttimes\fi{}2) reconstruction on the Si(001) surface. Again, single-crystal Ag(111) films are obtained; however, their in-plane orientation is now rotated by 90\ifmmode^\circ\else\textdegree\fi{}. In this case, the close-packed rows of Ag atoms are aligned parallel to the step edges.

Deposition of nonreacting metals on semiconductors usually results in three-dimensional islands that often exhibit a different crystal orientation than the substrate. Using the kinetic pathway of low temperature growth, a continuous and smooth Ag film with a (111) orientation is formed on Si(001). The interface planes fit nearly exactly within a (3\ifmmode\times\else\texttimes\fi{}4) unit cell of the Si(001) surface. The remaining small mismatch is adjusted by periodic arrays of interfacial defects. The orientation of the Ag(111) film is strictly determined by the orientation of the Si bonds: From step to step of the Si(001) substrate the Ag(111) crystallites rotate by 90 \ifmmode^\circ\else\textdegree\fi{}.

Deposition of Ag at 130 K results in epitaxial layer growth of a continuous Ag(1 1 1)-film on Si(100). The azimuthal orientation of the Ag(1 1 1)-crystallites is determined by the dimer rows of the Si(100) terraces and alternates by 90° from step to step of the Si substrate. In one direction the highly mismatched (100)- and (1 1 1)-lattices fit nearly exactly with a ratio of 4 Ag atoms to 3 Si atoms. In the other direction the remaining lattice mismatch of 2.2% is adjusted by a parallel array of interfacial dislocations which are observed with LEED (via spot splitting) and STM.

The step topography of 4°‐misoriented Si(001) surfaces was examined by scanning tunneling microscopy and spot profile analyzing–low‐energy electron diffraction. The clean Si(001)‐(2×1) surface proves to be a single domain substrate, which is characterized by a regular array of double steps. This step structure is changed dramatically upon adsorption of submonolayer quantities of Ag at ∼700 K. In this case, the formation of multisteps with fourfold, sixfold, and eightfold step heights occurs. The single domain character of the substrate is preserved, now showing a Ag‐induced (3×2) reconstruction.

Reconstructed structures of metal on Si(100)2×1 surfaces annealed at high temperature have been investigated by scanning tunneling microscopy as functions of the type of metal, coverage, and annealing temperature. The reconstruction mechanisms at high temperature depend on the type of metal. In the present paper, the formation mechanisms of reconstruction at high temperature are classified briefly into three categories and are discussed qualitatively.

We present scanning tunneling microscope (STM), low‐energy electron diffraction, Auger electron spectroscopy, and scanning electron microscope results on the growth of Ag on Si(001)(2×1). At room temperature Ag is adsorbed only at the silicon SB steps at first and preferentially forms dimers during further growth. At higher Ag coverages an inhomogeneous layer which does not cover the surface completely is formed and Ag islands grow with Ag(111)∥Si(001). At a substrate temperature of 770 K Ag forms a homogeneous layer which covers the surface completely. This layer shows a novel (2×3) reconstruction, which shows a strong bias polarity dependence in the STM images. On the top of this (2×3) layer, three‐dimensional Ag islands grow with Ag(001)∥Si(001).

Growth mode and surface structures of the Pb/Si(001) system have been investigated by scanning tunneling microscopy. The growth mode is the Stranski–Krastanov type and Pb grows layer by layer up to three layers before three dimensional (3D) nucleation of Pb islands occurs. The structure of the first layer changes from 2×2 and 2×1, passing through intermediate phases of 2×4 and c(8×4) with mixing by increasing Pb coverage. The second layer is a 2×1 structure, and the third layer is a c(4×4) structure. 3D islands of triangular shapes grow on the third layer of c(4×4) in an orientation of Pb(111)∥Si(001) at coverages higher than 2 monolayers.

We report on pronounced anomalies of the absorption and dispersion of the sound-induced rf magnetic field in superconducting YBa 2 Cu 3 O 7−δ ( δ K T K and for a near coincidence of the superconducting transition and a ferroelectric phase transition at about 90 K.

We report on ultrasonic experiments on YBa2Cu3O7. The formation of twins as a precursor of a first order phase transition is discussed.