High-field transport phenomenology: Hot-electron generation at semiconductor interfaces.
High-field transport phenomenology: Hot-electron generation at semiconductor interfaces.
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高场传输现象学：半导体界面处的热电子产生。
DOI：
10.1103/physrevb.36.6446
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Baeriswyl
中科院分区：
文献类型：
--
作者：
Blatter;Baeriswyl
使用现象学方法描述电子在大的不均匀电场中的传输。分别由电场和声子散射引起的载流子加速和减速的竞争效应由能量空间中的漂移扩散方程（福克-普朗克方程）描述。在福克-普朗克方程中，散射过程以平均方式处理：首先，非弹性散射产生平均摩擦力，该摩擦力抵抗电场的加速。其次，散射的随机特性引入了能量色散。电场和摩擦力的组合决定了粒子流在能量空间中的漂移，而能量色散项决定了粒子流的扩散。该形式应用于带电半导体界面耗尽区中热电子和少数载流子生成问题。摩擦力和能量色散是针对极性光学声子散射的情况确定的。考虑了声学声子散射和电子对产生。我们发现，在非常低的载流子能量下，极性光学声子散射的各向同性特征极大地增强了电子所经历的摩擦力。在低能量下产生的摩擦力峰值在大电场的存在下被抑制。因此，我们发现热电子和少数载流子生成的产率主要取决于半导体中施主浓度的场强。这些结果对压敏电阻的击穿行为具有影响。
The transport of electrons in large, inhomogeneous electric fields is described using a phenomenological approach. The competing effects of acceleration and deceleration of the carriers due to the electric field and the scattering by phonons, respectively, are described by a drift-diffusion equation (Fokker-Planck equation) in energy space. In the Fokker-Planck equation, the scattering processes are treated in an averaged manner: First, inelastic scattering gives rise to an average friction force, which opposes the acceleration by the electric field. Second, the random character of the scattering introduces an energy dispersion. The combination of electric field and friction force determines the drift of the particle flow in energy space, whereas the energy-dispersion term determines its diffusion. The formalism is applied to the problem of hot-electron and minority-carrier generation in the depletion region of charged semiconductor interfaces. The friction force and the energy dispersion are determined for the case of polar-optic-phonon scattering. Acoustic-phonon scattering and pair creation are taken into account. We find that the isotropic character of the polar-optic-phonon scattering at very low carrier energies greatly enhances the friction force experienced by the electrons. The resulting peak in the friction force found at low energies is suppressed in the presence of large electric fields. As a result, we find that the yields for hot-electron and minority-carrier generation depend critically on the field strength via the donor concentration in the semiconductor. These results have implications for the breakdown behavior of a varistor.