초록 ▼

Germanium and doped-germanium polycrystalline films are formed using photolytic CO2 laser-induced chemical vapor deposition method. Germanium being transparent to IR light makes the production of high purity polycrystalline germanium and doped-germanium films from starting compounds of germane, ethy

Germanium and doped-germanium polycrystalline films are formed using photolytic CO2 laser-induced chemical vapor deposition method. Germanium being transparent to IR light makes the production of high purity polycrystalline germanium and doped-germanium films from starting compounds of germane, ethylgermane diethylgermane, and triethylgermane ideally adapted to the laser induced infrared radiation provided by the tunable, continuous-wave CO2 laser which delivers infrared laser radiation in the range of 10.4 or 9.4 micrometers. Triethylgermane produces germanium in a quantity usable as a dopant. Scanning electron microscopy is used for analysis of the films. The products identified on irradiation of germane are germanium and hydrogen. Conversion rates on the order of 86% are readily obtained. On irradiation of diethylgermane and ethylgermane, ethylene, germane, germanium and hydrogen are produced. Germanium films doped with cadmium and aluminum are successfully produced by the irradiation of germane mixtures containing dimethylcadmium or trimethylaluminum, respectively. A starting material such as tetramethylgermane (TMG) which has a high vapor pressure, e.g. >70 torr and which does not have a frequency of vibration resonant with the output of the CO2 laser, is usable in the presence of a sensitizer, i.e., a substance is employed with tetramethylgermane which absorbs the energy and then subsequently reacts with a transfer energy to the TMG.

대표청구항 ▼

A method for infrared laser-induced chemical vapor deposition of polycrystalline germanium and doped-germanium films wherein in said method as said deposition increases in amount the rate of said deposition does not decrease because of the transparency of said deposited polycrystalline germanium or

A method for infrared laser-induced chemical vapor deposition of polycrystalline germanium and doped-germanium films wherein in said method as said deposition increases in amount the rate of said deposition does not decrease because of the transparency of said deposited polycrystalline germanium or doped-germanium films to the output frequencies of the infrared laser inducing said deposition, said method comprising: i. placing a prepared substrate into one or more laser reaction cells; ii. filling one or more laser reaction cells with one or more compounds selected from germane, ethylgermane, diethylgermane, triethylgermane, tetramethylgermane, dimethylcadmium, and trimethylaluminum to a predetermined pressure from about 3.5 to about 220 torr; iii. irradiating said compound with infrared laser radiation in the range of 10.4 or 9.4 micrometer as provided by a continuous-wave CO2 laser whose single-line operation is varied in output powers between 10 and 150 watts/cm2; iv. continuing said irradiating for a predetermined time period from about 15 seconds to about one minute to effect laser photochemical dissociation of said compound contained in said laser reaction cell; and, v. repeating said irradiating for an additional predetermined time period from about 15 seconds to about one minute as required to achieve said infrared laser-induced chemical vapor deposition of polycrystalline germanium or doped-germanium films.