Mechanism of Reverse Leakage Current in Schottky Diode Fabricated on Large Bandgap Semiconductors like Ga2O3 or Diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-05-01 |
| Journal | ECS Meeting Abstracts |
| Authors | W. S. Lau |
Abstract
Section titled âAbstractâThe bandgap of Ga 2 O 3 (4.5-4.9 eV) is larger than the bandgap of GaN (3.4 eV). In addition, single crystal bulk Ga 2 O 3 wafers can be more easily manufactured than GaN wafers. Therefore, Ga 2 O 3 has strong potential for applications in high power semiconductor devices [1]. Schottky diodes fabricated on n-type Ga 2 O 3 have strong potential as fast high-power switching devices. Similarly, the bandgap of diamond (5.5 eV) is very large and diamond Schottky diodes have good potential. For example, Harada et al. published their work on Schottky diodes fabricated on n-type Ga 2 O 3 with PdCoO 2 as the metal [2]. They claimed that their Schottky diodes have a very large Schottky barrier height of 1.8 eV. Other scientists using metals like W, Au, Ir, Pd or Pt cannot achieve such a large value of the Schottky barrier height. However, they did not propose any physical mechanism regarding the reverse leakage current in their Schottky diodes. One possible mechanism of reverse leakage current in Schottky diodes fabricated on n-type Ga 2 O 3 is image force barrier lowering at the metal-Ga 2 O 3 interface. Historically, there were 2 theories regarding the image force barrier lowering effect. In 1953, Krömer published his theory that the image force dielectric constant in the equation for Schottky emission should be equal to 1 [3]. Subsequently in 1964, Sze et al. published their theory that the image force dielectric constant in the equation for Schottky emission should be equal to n 2 [4], where n is the refractive index of the semiconductor in the infrared or visible light range. The theory of Sze et al. quickly became the dominating theory whereas Krömerâs theory essentially became a forgotten theory. For Ga 2 O 3 , n is approximately equal to 2 [5] and so n 2 is about 4. The author performed an analysis on the experimental data published by Harada et al. [2] and found that Krömerâs theory fit the experimental data from Harada et al. much better than the theory of Sze et al. Similarly, the author noticed that Krömerâs theory is better than the theory of Sze et al. for diamond Schottky diodes. In conclusion, the author pointed out that it is necessary to resurrect an old and forgotten theory from Krömer in order to explain the experimental data on the reverse leakage current of Schottky diodes fabricated on large bandgap semiconductors like Ga 2 O 3 and diamond. References [1] M. Higashiwaki, H. Murakami, Y. Kumagai and A. Kuramata, Jpn. J. Appl. Phys. , 55 , 1202A1 (2016). [2] T. Harada, S. Ito and A. Tsukazaki, Sci. Adv. , 5 , eaax5733 (2019). [3] H. Krömer, Zeitschrift fur Physik , 134 , 435 (1953). [4] S.M. Sze, C.R. Crowell and D. Kahng, J. Appl. Phys. , 35 , 2534 (1964). [5] T. Onuma, S. Saito, K. Sasaki, T. Matsui, T. Yamaguchi, T. Honda, A. Kuramata and M. Higashiwaki, Jpn. J. Appl. Phys. , 55 , 1202B2 (2016).