Method for making amorphous semiconductor thin films

    公开(公告)号:US3862857A

    公开(公告)日:1975-01-28

    申请号:US31832972

    申请日:1972-12-26

    Applicant: IBM

    CPC classification number: C23C14/24

    Abstract: A method for providing an amorphous semicondcutor material thin film on a substrate member is described. In carrying out the method, there are disposed in spaced relationship in an evacuated chamber, a surface of a body of the semiconductor material which contains the constituents of the desired thin film in substantially stoichiometric proportion, the body being substantially uniform in thickness and in composition, and a surface of the substrate member. The distance between the two surfaces is chosen to be no greater than the shortest dimension of the surface of the semiconductor body, the area of the latter surface being chosen to be at least equal to the area of the surface of the substrate member. The semiconductor material contains semiconductor components, each of which has a high enough vapor pressure at a temperature less than its melting point to meet the criterion wherein the ratio P/(MTm)1/2, wherein P is the vapor pressure in Torr, M and Tm are molecular weight and melting points (in degrees Kelvin), respectively, has a value of at least 0.855 X 10 8. The surface of the semiconductor material body is uniformly heated to a temperature close to but less than its melting point to cause the semiconductor material thereof to evaporate therefrom onto the surface of the substrate member and to deposit on the substrate member''s surface as an amorphous film. In the situation wherein it is desired to deposit an amorphous semiconductor material thin film wherein the vapor pressure of one of the constituents is not sufficiently high at a temperature less than its melting point to meet the abovementioned ratio criterion, then, in the method, those components which have a sufficiently high vapor pressure at temperatures below their melting points to meet the criterion are combined in the desired stoichiometric proportions in a single semiconductor material body to provide a first sublimation source and those components which do not have sufficiently high vapor pressures at temperatures below the melting point of the semiconductor material to meet the above set forth ratio criterion function as separate sublimation sources. In this situation, the surface of the semiconductor body having the sufficiently high vapor pressure components is heated to a temperature close to but less than its melting point as in the single source method, and the sublimation sources comprising the low vapor pressure semiconductor constituents are positioned close to and adjacent to the first source, the latter sources being heated whereby their deposition rates onto the substrate are at the amounts required to provide their stoichiometric proportions in the thin film deposited on the substrate.

    OPTICAL MEMORY DEVICE
    7.
    发明专利

    公开(公告)号:JPH10177721A

    公开(公告)日:1998-06-30

    申请号:JP31361897

    申请日:1997-11-14

    Applicant: IBM

    Abstract: PROBLEM TO BE SOLVED: To obtain an optical memory medium based on completely novel memory principle and to obtain an optical memory device using this medium by recording data corresponding to characteristics of an amorphous solid selected from a group of materials each having refractive index and reflectance. SOLUTION: The amorphous solid is selected from a group of diamond-like carbon, silicon carbide, boron carbide, boron nitride, amorphous silicon and amorphous germanium, and the solid contains hydrogen by up to 50 atm% with covalent bonds. A specified region of the amorphous solid having a first refractive index and having atoms with covalent bonds is heated with laser light to change the refractive index in the heated area to a second refractive index. Thus, two states can be produced to correspond the memory of data without dissolving or crystallizing the amorphous solid. The density of the solid is changed by heating, which accompanies changes in the refractive index and reflectance.

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