The role of water (H₂O) vapor in reducing background impurity concentration in epitaxial Ga₂O₃ thin films grown by metalorganic chemical vapor deposition (MOCVD) was studied. Adding H₂O vapor to oxygen was found to increase the surface roughness and decrease the carrier concentration but have no effect on the structural quality and RT electron mobility of both the UID and doped films. The H₂O vapor promotes the growth of the stable (110) and $\left(\overline{1}10\right)$ facets elongated along the [001] direction. Using [H₂O] of 250 ppm, the β-Ga₂O₃ films showed a RMS roughness of >13 nm, which is much higher than that measured for similar films grown without H₂O (RMS = 0.8 nm). The electron mobility of the UID Ga₂O₃ layers grown with and without water vapor was ∼150 cm²/V s, while the carrier concentration dropped by ∼2.5× after increasing the [H₂O] to 6000 ppm. Similarly, for the lightly Si doped films, the RT carrier concentration dropped from 5.4 × 10¹⁵ cm⁻³ ([H₂O] = 0 ppm) to 3.4 × 10¹⁵ cm⁻³ ([H₂O] = 250 ppm), leaving the mobility unaffected. The results offer a new method of using water vapor assisted growth of Ga₂O₃ films with low RT carrier concentration that are required for the realization of high-performance electronic power devices with high breakdown voltages.

中文翻译：

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MOCVD制得的水蒸气辅助β-Ga2O3的生长

研究了水（H ₂ O）蒸气在通过有机金属化学气相沉积（MOCVD）生长的外延Ga ₂ O ₃薄膜中降低背景杂质浓度的作用。已发现向氧气中添加H ₂ O蒸气会增加表面粗糙度并降低载流子浓度，但对UID和掺杂膜的结构质量和RT电子迁移率均没有影响。H ₂ O蒸气促进马the（110）和$\left(\overline{\mathrm{1个}}10\right)$沿[001]方向拉长的小面。使用[H ₂ O]为250ppm时，的β-Ga ₂ ö ₃片显示RMS粗糙度> 13纳米，这比由不ħ生长类似薄膜测定高得多的₂ O（RMS = 0.8纳米）。在有和没有水蒸气的情况下生长的UID Ga ₂ O ₃层的电子迁移率约为150 cm ² / V s，而当[H ₂ O]增加至6000 ppm后，载流子浓度下降了约2.5倍。类似地，对于轻掺杂的Si薄膜，RT载流子浓度从5.4×10 ¹⁵ cm ^-3（[H ₂ O] = 0 ppm）降至3.4×10 ¹⁵ cm^-3（[H ₂ O] = 250 ppm），迁移率不受影响。结果提供了一种使用水蒸气辅助生长具有低RT载流子浓度的Ga ₂ O ₃膜的新方法，这是实现具有高击穿电压的高性能电子功率器件所必需的。