GaAs中的低温Zn扩散

本文研究了低温条件下Zn向GaAs中的扩散。实验是用ZnAs2源在抽真空的石英管中进行的。研究了结深Xj,扩散温度T和扩散时间t的关系。结果表明,表面层电阻Rs随Xj,的增加而降低;表面浓度Cs随1/T的增加而降低;迁移率随Cs的增加而降低。将Cs对1/(RsXj)作图表明,Cs随1/(RsXj)的增加而增加。这一关系可作为判断多层GaAlAs/GaAs外延层扩Zn后表面浓度的简便方法。文中讨论了Zn在GaAs和InP中的扩散机理,比较了Zn在InP和GaAs扩散层中的参数。 该扩散工艺可获得表面光亮、无损伤的高浓度表面层,并已在GaAs/Ga1-xAlxAs双异质结发光管的制备工艺中应用。制得了光输出功率为24mW、串联电阻为35、压降为2.4V的GaAs/Ga1-xAlxAs双异质结发光管。

THE DIFFUSION OF Zn IN GaAs AT LOW TEMPERATURE

In this report the diffusion of Zn into GaAs at low temperature has been investigated. The experiments are accomplished in an evacuated and sealed quartz ampoule using ZnAs₂ as the source of Zn.The relation among the junction depth (X_j), the time (t) and the temperature (T) of diffusion has been investigated. It is found that the sheet resistance (R_s) of diffu-sion layer increases as the junetion depth (X_j) decreases, the surface concentration (C₂) decreases as 1/T increases and the carrier mobility (μ) decreases as C_s increases. The C_s vs. 1/X_jR_s is plotted, it indicates that the C_s increases as 1/(X_jR_s) inereases. This is a simple method for determining the C_s of the multiple Ga_1-xAl_xAs/GaAs epitaxial layer. The mechanism of Zn diffusion in GaAs and InP is discussed. This process has been applied to fabricate GaAlAs/GaAs double heterojunction light emitting idodes and an output power of 2-4 mW and a series resistance of 3-5Ω are obtained.