Growth condition of iodine-doped n+-CdTe layers in metal-organic vapor phase epitaxy
Growth condition of iodine-doped n+-CdTe layers in metal-organic vapor phase epitaxy
复制标题
金属有机气相外延碘掺杂n-CdTe层的生长条件
DOI：
10.1007/s11664-002-0236-y
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发表时间：
2002
影响因子：
2.1
通讯作者：
Y. Agata
中科院分区：
文献类型：
--
作者：
K. Yasuda;Y. Tomita;Y. Masuda;T. Ishiguro;Y. Kawauchi;H. Morishita;Y. Agata
以二乙基碲化物（DETe）和二异丙基碲化物（DiPTe）为碲源，乙基碘（EI）为掺杂剂，研究了金属有机气相外延（MOVPE）法在（100）GaAs衬底上生长CdTe薄膜的碘掺杂。随着生长温度从425°C降低到325°C，掺杂层的电子密度逐渐增加。用DETe生长的掺杂层具有比用DiPTe生长的掺杂层更高的电子密度。当生长温度为325°C时，热壁温度从200°C增加到250°C时，用DETe生长的掺杂层显示出电子密度从3.7× 1016 cm-3增加到2.6× 1018 cm-3。另一方面，对于用DiPTe生长的层，没有观察到电子密度的这种增加。根据这些前驱体的生长特性，研究了DETe和DiPTe不同掺杂特性的机理。DETe比DiPTe具有更高的热稳定性被认为是导致掺杂性能差异的原因。随着热壁温度从200°C增加到250°C，对于用DETe生长的层，生长表面上的Cd与Te物种的有效比率变得比用DiPTe生长的大。这被认为是减少掺杂碘的补偿和增加与DETe生长的层的电子密度。随着生长温度的降低，生长表面上的Cd与Te物种的有效比率也增加。这被认为是随着生长温度的降低而增加电子密度。
Iodine doping of CdTe layers grown on (100) GaAs by metal-organic vapor phase epitaxy (MOVPE) was studied using diethyltelluride (DETe) and diisopropyltelluride (DiPTe) as tellurium precursors and ethyliodine (EI) as a dopant. Electron densities of doped layers increased gradually with decreasing the growth temperature from 425°C to 325°C. Doped layers grown with DETe had higher electron densities than those grown with DiPTe. When the hot-wall temperature was increased from 200°C to 250°C at the growth temperature of 325°C, doped layers grown with DETe showed an increase of the electron density from 3.7×1016cm−3to 2.6×1018cm−3. On the other hand, such an increase of the electron density was not observed for layers grown with DiPTe. The mechanisms for different doping properties for DETe and DiPTe were studied on the basis of the growth characteristics for these precursors. Higher thermal stability of DETe than that of DiPTe was considered to cause the difference of doping properties. With increasing the hot-wall temperature from 200°C to 250°C, the effective ratio of Cd to Te species on the growth surface became larger for layers grown with DETe than those grown with DiPTe. This was considered to decrease the compensation of doped iodine and to increase the electron density of layers grown with DETe. The effective ratio of Cd to Te species on the growth surface also increased with decreasing growth temperature. This was considered to increase the electron density with decreasing growth temperature.