Mechanism of Reverse Leakage Current in Schottky Diode Fabricated on Large Bandgap Semiconductors like Ga2O3 or Diamond Part II
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-07-07 |
| Journal | ECS Meeting Abstracts |
| Authors | W. S. Lau |
| Institutions | Nanyang Technological University |
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. One possible mechanism of reverse leakage current in Schottky diodes is image force barrier lowering at the metal-semiconductor 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 [2]. 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 [3], where n is the refractive index of the semiconductor in the infrared or visible light range. In 1969, Sze published a book which has influenced many scientists [4]. Szeâs theory [3]-[4] quickly became the dominating theory whereas Krömerâs theory essentially became a forgotten theory. In 2020, the author pointed out that Krömerâs theory is quite frequently more compatible with experimental results for Ga 2 O 3 or diamond Schottky diodes [5]. In 2021, the author attempted to propose a new theory involving the concept of electron velocity overshoot to unify Krömerâs theory and Szeâs theory, as shown in Fig. 1 [6]; Krömerâs theory is better than Szeâs theory for high reverse bias voltage. 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, etc. A theoretical basis based on quasi-ballistic transport will be provided. References [1] M. Higashiwaki, H. Murakami, Y. Kumagai and A. Kuramata, Jpn. J. Appl. Phys. , 55 , 1202A1 (2016). [2] H. Krömer, Zeitschrift fur Physik , 134 , 435 (1953). (In German.) [3] S.M. Sze, C.R. Crowell and D. Kahng, J. Appl. Phys. , 35 , 2534 (1964). [4] S.M. Sze, Physics of Semiconductor Devices , p. 367, Wiley Interscience, New York (1969). [5] W.S. Lau, ECS Trans. 97 (4) , 99 (2020). [6] W.S. Lau, CSTIC 2021 (China Semiconductor Technology International Conference, Shanghai, 2021, IEEE), 1 (2021). (Available from IEEE database.) Figure 1