Gradient freeze method

Earlier work was carried out with crystalline bulk InP samples prepared by the gradient freeze method [274]. As In could become scarce due to its present use in electronics [275], the use of bulk material appears too expensive for appHcations. Therefore, homoepitaxial thin films have been prepared on InP wafers which can be removed by estabhshed Hft-off techniques [276]. The preparation by MOVPE allows scaling up and fine tuning of the growth process, enabhng fabrication of films with high electronic quality [277]. Besides the hitherto used (111) A-face (see Section 2.4.2.1), the surprisingly stable In-rich (100) surface is considered here. 

Fig. 5.1 Schematic principle of (a) the vertical gradient freeze method and (b) the vertical Bridgman method.

W.A. Gault, E.M. Monberg, and J.E. Clemans, 1986, A novel application of the Vertical Gradient Freeze method to the growth of high quality lll-V crystals , J. Cryst. Growth 74, 491-506. 

Crystal-Growth Technology for Ternary lll-V Semiconductor Production by Vertical Bridgman and Vertical Gradient Freezing Methods with Accelerated Crucible Rotation Technique... 

T. Asahi, K. Kainosho, K. Kohiro, A. Noda, K. Sato, O. Oda, 2003, Growth of III-V and II-VI Single Crystals by the Vertical Gradient-freeze Method, in Crystal Growth Technology, (eds.)... 

A variation of the Bridgman method is the gradient freeze method. In the simplest case, the base of the ampoule sits on a quench block or otherwise cooled. The temperature of the furnace is gradually lowered in a controlled manner, which decreases the temperature gradient in the sample and advances the solidification isotherm. Single crystal turbine blades are usually grown in this manner. The advantage is simplicity—there are no... 

VGF Vertical-Gradient Freezing rather rare method of constant-cooling solidification in a vertical temperature gradient ZM (Joule Heat) Zone Melting first simple method of directional solidifica-... 

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