S－GaAs表面键对砷化镓电性能的影响

EFFECT OF S-GaAs SURFACE BONDS ON GaAs ELECTRONIC PROPERTY

砷化镓表面经硫化钠水溶液处理后，其电学性能得到很好的改善。实验样品的电容电压特性曲线发生变化，势垒电容变大。Ｘ射线光电子谱揭示样品表面氧的成分大大减少，砷的结合能由原来的１３２１．４７ｅＶ变为１３２１．００ｅＶ，Ａｓ（２Ｐ＿（３／２））芯能级移位０．４７ｅＶ。砷化镓表面形成Ｓ－Ａｓ键，改善了表面费米能级的钉札，减少了表面态密度及表面复合中心。

The electronic properties of GaAa are dramatically improved in samplestreated with aqueous solntion of sodinm sulfide nonahydrate (Na_2S·9H_2O).Experimental results show that the characteristic curves of capacitance-voltage(C-V) vary shape for the Na_2S·9H_2O treated samples, and that its potential barriercapacitance is higher than that of the untreated sample. The X-ray phtoelectronspectroscopy (XPS) reveals that the oxygen on the GaAs surface treated withNa_2S·9H_2O is remarkably removed, and that the peak of the binding energy of Asvaries from the background peak 1321 .00 eV to 1321 .47 eV, a shift of 0 .47 ey. Thesulfur depth profile on the GaAs surface is determined by the secondary ion massspectroscopy (SIMS). New S-As bonds and compound of arsenic sulfide are formedon the GaAs surface, making the “pinned”Fermi level improved. The surfacestate density and surface recombination center on the sodium salfide treatmentsample have been greatly reduced, which is favorable for controlling the chargein GaAs.