Lowering of the Schottky barrier height of metal/n-type 4H-SiC contacts using low-work-function metals with thin insulator insertion
Lowering of the Schottky barrier height of metal/n-type 4H-SiC contacts using low-work-function metals with thin insulator insertion
复制标题
DOI：
10.35848/1347-4065/ac0ab2
复制
发表时间：
2021
影响因子：
1.5
通讯作者：
T. Doi;S. Shibayama;M. Sakashita;M. Shimizu;O. Nakatsuka
中科院分区：
文献类型：
--
作者：
T. Doi;S. Shibayama;M. Sakashita;M. Shimizu;O. Nakatsuka
我们研究了使用低功函数金属以通过低温工艺实现欧姆接触的金属/n型4 H-碳化硅（SiC）接触的肖特基势垒高度（SBH）的降低。我们发现Y、Mg和Hf/n型4 H-SiC接触的SBH偏离了肖特基极限，并且SBH至少大于0.5 eV。在Mg/n型4 H-SiC界面插入0.3和0.7 nm厚的SiN x层可以有效地降低SBH，Mg/SiN x /n型4 H-SiC的SBH低至0.36 eV。SBH的这种减少可以归因于在导带边缘表现出的金属诱导的间隙状态的抑制。最后，通过定量分析，证明了在施主浓度低于103 × 1019 cm-3时，Mg/SiN x（0.3 nm）/4 H-SiC界面的接触电阻率与Mg/4 H-SiC界面的接触电阻率相比可以降低大约一个数量级。
We examined the lowering of the Schottky barrier height (SBH) of a metal/n-type 4H-silicon carbide (SiC) contact using low-work-function metals to realize an ohmic contact through a low-temperature process. We found that the SBHs of Y, Mg, and Hf/n-type 4H-SiC contacts deviated from the Schottky limit and that the SBH was greater than ∼0.5 eV at minimum. Inserting 0.3 and 0.7 nm thick SiN x layers into a Mg/n-type 4H-SiC interface could help effectively reduce the SBH; Mg/SiN x /n-type 4H-SiC exhibited an SBH as low as ∼0.36 eV. This reduction in the SBH could be attributed to the suppression of the metal-induced gap state manifested at the conduction band edge. Finally, through a quantitative analysis, it was demonstrated that the contact resistivity of a Mg/SiN x (0.3 nm)/4H-SiC interface could be reduced by approximately one order of magnitude compared with that of a Mg/4H-SiC interface at donor concentrations below ∼3 × 1019 cm−3.