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arXiv 2103.16639cond-mat.mtrl-sci
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Ga2O3三步合成的费米能级工程和掺杂型转换

Computational Fermi level engineering and doping-type conversion of Ga2O3 via three-step synthesis process

Anuj Goyal, Andriy Zakutayev, Vladan Stevanović, Stephan Lany

摘要:

Ga 2 O3正在积极探索用于高功率和高温电子学,深紫外光电子学和其他应用。Ga 2 O3的高效n型掺杂已经实现,但p型掺杂由于补偿、深受体能级和自由空穴的极化子传输机制而面临根本性障碍。然而,除了实现p型导电性之外,还存在大量的机会来设计费米能级的位置,以改进基于Ga 2 O3的器件的设计。我们使用第一性原理缺陷理论和缺陷平衡计算来模拟3步生长-退火-淬火合成协议的氢辅助镁掺杂β-Ga 2 O 3,考虑到气体之间的相平衡H2,O2和H2 O,这决定了H的化学势。我们预测Ga 2 O3掺杂型转换后的净p-型制度的生长在还原条件下,在H2的存在下,然后通过富氧退火,这是一个类似的过程中的Mg受体激活的H去除GAN。对于平衡退火,对于给定的Mg掺杂水平,存在最大化Ga 2 O3净受主密度的最佳温度,其在没有再平衡的非平衡退火情况下进一步增加。在淬火到工作温度后,Ga 2 O 3费米能级下降到中能隙以下,下降到价带最大值以上约+1.5 eV,产生大量未补偿的中性MgGa 0受主。这种掺杂型转换(NA > ND)Ga_2 O_3材料的费米能级降低到+1.5 eV,并抑制了自由电子密度,对Ga_2 O_3功率电子器件的设计具有重要意义和影响。

英文摘要:

Ga2O3 is being actively explored for high-power and high-temperature electronics, deep-ultraviolet optoelectronics, and other applications. Efficient n-type doping of Ga2O3 has been achieved, but p-type doping faces fundamental obstacles due to compensation, deep acceptor levels, and the polaron transport mechanism of free holes. However, aside from achieving p-type conductivity, plenty of opportunity exists to engineer the position of the Fermi level for improved design of Ga2O3 based devices. We use first-principles defect theory and defect equilibrium calculations to simulate a 3-step growth-annealing-quench synthesis protocol for hydrogen assisted Mg doping in beta-Ga2O3, taking into account the gas phase equilibrium between H2, O2 and H2O, which determines the H chemical potential. We predict Ga2O3 doping-type conversion to a net p-type regime after growth under reducing conditions in the presence of H2 followed by O-rich annealing, which is a similar process to the Mg acceptor activation by H removal in GaN. For equilibrium annealing there is an optimal temperature that maximizes the Ga2O3 net acceptor density for a given Mg doping level, which is further increased in the non-equilibrium annealing scenario without re-equilibration. After quenching to operating temperature, the Ga2O3 Fermi level drops below mid-gap down to about +1.5 eV above the valence band maximum, creating a significant number of uncompensated neutral MgGa0 acceptors. The Fermi level reduction down to +1.5 eV and suppression of free electron density in this doping type converted (NA > ND) Ga2O3 material is of significance and impact for the design of Ga2O3 power electronics devices.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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