Showing papers on "Pulsed laser deposition published in 1978"

Some features of laser annealing of implanted silicon layers

Abstract: Comparative investigation of the process of the structure reordering of disordered implanted silicon layers after thermal (800°C, 30 min) and pulse laser annealing have been carried out. The new laser method of annealing implanted layers has a number of interesting features which provide great efficiency and locality of semiconductor doping without considerable heating of the base material and redistribution of implanted impurities. On the base analysing of investigation of kinetics of layer photostimulated recrystallization and calculation of temperature fields the possible mechanisms of laser annealing are also discussed.

Chemical vapor deposition of silicon using a CO2 laser

Abstract: Chemical vapor deposition of polycrystalline silicon is reported in which a CO2 laser is used for substrate heating. With this technique, deposition can be spatially limited to only a small portion of the substrate, and a spatial resolution of 50 μ is demonstrated. Since the reaction chamber and majority of the substrate are at much lower temperatures, premature gas phase reactions and substrate etching are avoided.

Structure of crystallized layers by laser annealing of 〈100〉 and 〈111〉 self-implanted silicon samples

Abstract: Channeling effect techniques with a 2.0 MeV He+ Rutherford backscattering and transmission electron microscopy were used to characterize the crystallized layers after Q-switched ruby laser irradiation of 4000 A thick amorphous layer on 〈100〉 and 〈111〉 underlined crystal substrates. At a laser energy density of 2.5 J/cm2 the crystal layer on the 〈111〉 specimen contains a large density of stacking-faults, that on 〈100〉 specimen contains a very small amount of screw dislocation lines. High quality single-crystal layers have been obtained after irradiation at 3.5 J/cm2. From a comparison with the growth rate and defect structure observed in thermally annealed implanted-amorphous layers, we propose that crystal growth by 50 ns pulse laser annealing occurs by melting the amorphous layer.

Apparatus for multilayer thin film deposition

Abstract: Apparatus for sputter depositing two or more layers of material onto a substrate in one operation includes an evacuable chamber containing a transport mechanism, substrate support, and at least two deposition units situated proximate the support. The transport mechanism moves the substrate to and from the support. When at the support, the substrate is passed by one deposition unit and then the other for sputter deposition of a thin film of material by each unit.

The role of a catalyst in the isotopically excited laser photochemistry

Abstract: Laser photochemistry of Bcl3/H2 using catalysis was carried out experimentally. The 10.55 μm radiation from a high power (G W/cm2) TEA CO2 pulse laser was used to selectively excite the 11Bcl3 molecules. Using Ti catalyst the reaction products analyzed were 10B11BH2Cl4, 11B11BH2Cl4, and HCl, whereas those were 10B11Bcl4, 11B11Bcl4, and HCl when Pb metal powder was employed, i.e., 10B10BH2Cl4 and 10B10Bcl4 molecules were not generated in our experiment. Moreover, it was found that the 10Bcl3 concentration in the unreacted Bcl3 gas increased from 20% to 37% after 360 laser pulses, but the isotopic enrichment was not obtained for the reaction products. The mechanisms for the observed catalytic laser photochemistry are proposed.

Method of making a semiconductor light-emitting device utilizing low-temperature vapor-phase deposition

Abstract: In order to decrease threshold current of a semiconductor laser, and to obtain a single mode lasing suitable for use in light-communication, the semiconductor laser is formed in stripe type in which the light-emitting (i.e., active) layer and neighboring layers are formed in mesa-etched stripe type and low impurity-concentration (i.e., high resistivity) layers of GaAs, GaAsP or GaAlAs are situated to contact the mesa-etched side faces of the stripe-shaped part on the semiconductor device by vapor phase growth, vacuum deposition, sputtering, or molecular beam deposition. Since the wafer temperature can be kept fairly low (e.g. 400°-700° C.) in comparison with that (about 950° C.) in a liquid phase growth, the stress introduced during the deposition is smaller than that in a liquid phase growth.

Parameters of a plasma formed by the action of microsecond laser pulses on an aluminum target in vacuum

Abstract: The results are given of a numerical solution of the one-dimensional (plane) time-dependent radiative–gasdynamic problem of the action of laser radiation of wave lengths in the range 0.1–1 μ on an aluminum target in a vacuum. It is shown that the emission of thermal radiation originating in the ablation plasma lowers its temperature substantially. A considerable fraction of the incident laser energy (up to 30–40 %) is emitted into vacuum from a plasma jet in a spectrum which extends into the UV and vacuum UV regions.

Method for vapor depositing a cerium oxide film

Abstract: A method for forming a thin film of cerium oxide as a blocking layer which constitutes a portion of a photoelectric film of a blocking type image pickup tube is disclosed. A substrate deposition rate in a vacuum deposition process is established in a range between 0.01 to 0.6 A/sec to prevent the deposition of particles which result in black or white spots in a picture image. It is more effective to select a particle size of 5 μ or more for the primary particles to be deposited.

Growth Kinetics of Thin Films by Molecular Beam Deposition

Abstract: 最近,分 子線蒸着(molecular beam deposition)法 が 注 目をあび1,2),この方法 を用 いたエピタキシャル膜 の成 長機構 の研究が さかんに行 なわれるよ うになった3・4・5). しか し,分 子線蒸着法 が具体的 に どのよ うな ものを指 す かについては,い くつかの異 った考 え方 があ り,ど の よ うな立場 に立つかに よって,お のず と問題 の とらえ方 も異 って くる. 第一の立場 は,蒸 発源 と基板 の間を蒸 発分子 が衝 突す ることな く,飛 行 できるよ うな条件下での蒸 着であ ると い う考 え方である.こ の場合には,根 本的には装置の真 空度が問題になるのであるが,従 来の真空蒸着法は,ほ とんどが この条件 をみ たす.し たが って,こ の立場に立 てば,分 子線蒸着法 は今 までの方法 となん ら変 りはない ことになる. 第二 の立場は,蒸 着分子 をコ リメー トして,い わ ゆる ビーム状 にし,基 板 に到達 させ る方法 である.こ の立場 は,蒸 着分子が ビーム状 になっているので感覚的 には分 子線蒸着法 と呼ぶ ことが納得 できる. 第三の立場 は,第 二の条 件をみた した上 に,蒸 着 の過 程を測定,制 御す ることのできる種 々の装置 を とりつけ た真空槽 中での蒸着で ある.こ のよ うな方法 が用 い られ るようになったのは,十 分な制御 を必要 とする高 品質 の 化合物半導体薄膜 を製作す ることに対(する必要性 か らで ある. これ ら三つの立場 の ど れ に 立 って も,分 子線蒸 着法 は,基 本的には,従 来 の蒸着法 と,膜 の成長機 構におい ては変 りのない ものである.但 し,CdS,GaAs,CdSe等 の蒸気圧 の高 い材料 を含 む薄膜の成長の場合 には,こ れ らの蒸着材料 が基板 まで,ど の様な過 程で到 達 す る か は,実 用的 な見地 か ら非 常に重 要な ことで ある6).不 必 要 な個所 に蒸着材料 が到達 しない よ うにすれば・周囲 の 壁 な どか らの基板面 への蒸着材料の まわ りこみ な どとい う制御 の困難 な要 因を除 くことがで き,化 合物半導体薄 膜 の蒸着 には,十 分に意 味の あるこ とで ある. このよ うな ことか ら,厳 密 な意味 か らは,第 一 の立場 が正 しいであ ろうが,第 三の立場 に立 って,分 子線蒸着 法を考 えるのが,現 在の主流 とい えよ う. 本 稿で も,主 として,第 三 の立場 に立 って,分 子線蒸 着膜の成長機構 につい ての研究 の現在 までの成 果にっい てふれ るこ とにす る.