Dependence of Seebeck Coefficient on Carrier Concentration in Heavily B- and P-Doped Si1-xGex (x≦0.05) System
Dependence of Seebeck Coefficient on Carrier Concentration in Heavily B- and P-Doped Si1-xGex (x≦0.05) System
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DOI：
10.1143/jjap.38.6394
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发表时间：
1999-11
影响因子：
1.5
通讯作者：
O. Yamashita;N. Sadatomi
中科院分区：
文献类型：
--
作者：
O. Yamashita;N. Sadatomi
测量了电弧熔炼法制备的掺B和P的Si、Si 0.97 Ge 0.03和Si 0.95 Ge 0.05的电阻率ρ、Seebeck系数S和载流子迁移率μ随载流子浓度n的变化。发现在约2×1020 cm-3的高载流子浓度下，具有掺杂偏析的Si_（0.97）Ge_（0.03）和Si_（0.95）Ge_（0.05）样品的S值比先前在具有少量偏析的Si_（0.95）Ge_（0.05）、Si_（0.85）Ge_（0.15）和Si_（0.7）Ge_（0.3）样品上测量的S值高约50%，尽管它们的ρ值之间的差异非常小。最显著的结果是，掺杂Si样品的S曲线在掺杂浓度约为3×1019 cm-3时出现一个峰，而Si_（0.97）Ge_（0.03）样品没有观察到象Si_（0.7）Ge_（0.3）合金那样的峰。这样的峰是令人惊讶的，因为它与传统理论相冲突，传统理论预测S随n的增加而单调减少。这种现象与掺杂剂偏析导致的有效质量的变化有关。
The electrical resistivity ρ, the Seebeck coefficient S and the carrier mobility µ were measured as a function of carrier concentration n for B- and P-doped Si, Si0.97Ge0.03 and Si0.95Ge0.05 prepared by arc melting. It was found that at a high carrier concentration of about 2×1020 cm-3, the S values of the Si0.97Ge0.03 and Si0.95Ge0.05 samples with dopant segregations are about 50% higher than those measured previously on Si0.95Ge0.05, Si0.85Ge0.15 and Si0.7Ge0.3 samples with little segregation, although the differences between their ρ values are very small. The most striking result is that the S curves of the doped Si samples have a hump at a concentration of about 3×1019 cm-3, while no hump was observed for the Si0.97Ge0.03 samples, as in the case of Si0.7Ge0.3 alloys. Such a hump is surprising because it conflicts with the conventional theory that predicts a monotonic decrease of S with increasing n. This phenomenon is related to a change in the effective mass which results from dopant segregation.