Modulation of Growth Rate by Electric Current in Liquid-Phase Epitaxy of 4H-SiC
The crystallization of 4H-SiC from Si--C solution in liquid-phase electroepitaxy (LPEE) at 1870 and 2050 °C was investigated. The growth of 4H-SiC was enhanced or suppressed by the application of DC with positive or negative polarity, respectively. By the application of AC, the Joule heating effect...
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| Published in | Japanese Journal of Applied Physics Vol. 52; no. 8; pp. 085503 - 085503-6 |
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| Main Authors | , , , , , |
| Format | Journal Article |
| Language | English |
| Published |
The Japan Society of Applied Physics
01.08.2013
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| Subjects | |
| Online Access | Get full text |
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| Summary: | The crystallization of 4H-SiC from Si--C solution in liquid-phase electroepitaxy (LPEE) at 1870 and 2050 °C was investigated. The growth of 4H-SiC was enhanced or suppressed by the application of DC with positive or negative polarity, respectively. By the application of AC, the Joule heating effect was separated from the effect of DC on LPEE. We showed that the effect of DC on LPEE consists of a linear electromigration effect and a quadratic Joule heating effect. The results demonstrate that growth rate can be controlled by adjusting not only temperature but also electric current. The variation of growth rate with temperature in LPEE was also examined, and it was shown that the electromigration effect can be controlled independently of the Joule heating effect by increasing the C concentration in the Si--C solution. At higher temperatures, the growth rate in LPEE can be improved without the enhancement of the Joule heating effect. |
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| Bibliography: | Schematic illustration of the experimental setup and the seed structure used in this study: (a) setup for the LPEE experiment in the furnace and (b) seed structure with the 25-mm-long 4H-SiC crystal. Temperature sequence in the LPEE experiment at 1870 °C: (I) prebaking in a vacuum of less than 1 Pa, (II) preheating under He atmosphere, (III) LPEE growth, and (IV) separation of the seed crystal from the solvent and cooling. $I$--$V$ characteristics of the 4H-SiC seed crystal ( ) and a thin graphite rod with the same shape as the seed crystal ( ) measured under the growth conditions at 1870 °C. Transmission optical micrographs of the cross sections of seeds after LPEE growth at 1870 °C for 3 h (a) with a DC of 0.8 A with negative polarity, (b) with no electric current, and (c) with a DC of 0.8 A with positive polarity. (d) Growth rate plotted as a function of DC polarity. Change in growth rate as a function of electric current and polarity in the LPEE at 1870 °C. The difference between the growth rates with and without electric current is shown. Solid circles and open squares show the results of LPEE with DC and 50 Hz AC, respectively. Fitting curves a and c indicate the changes in growth rate corresponding to $G_{\text{J}}$ and $G_{\text{EM}}+G_{\text{J}}$, respectively. Line b corresponds to $G_{\text{EM}}$, which is evaluated from fitting curves a and c. Optical micrographs of the growth surface after the LPEE at 1870 °C for 3 h (a) with a DC of 0.6 A with negative polarity, (b) with no electric current, and (c) with a DC of 0.6 A with positive polarity. Change in growth rate as a function of the DC in the LPEE at 2050 °C ( ). The difference between the growth rates with and without electric current is shown. Open circles indicate the growth rate that the contribution of Joule heat is subtracted in accordance with the quadratic Joule effect in Fig. . The solid line is fitted to the data corresponding to the linear electromigration effect ( ). ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0021-4922 1347-4065 |
| DOI: | 10.7567/JJAP.52.085503 |