合金条件对Al/n~+-Ge欧姆接触的影响

Abstract

gE比SI具有更高的电子和空穴迁移率,且gE材料可以应用于1.3~1.5μM近红外波段,因此gE成为制备微电子和光电子器件的主要材料。然而由于gE的费密能级钉扎效应以及难以获得高浓度的磷(P)原位掺杂,使得n-gE的欧姆接触成为一个难题。采用P+离子注入获得高掺杂浓度的n-gE材料,掺杂浓度为1.5x1019CM-3;依据圆形传输线模型(CTlM)制备了一系列Al/n+-gE样品,研究了不同退火温度和退火方式对其接触特性的影响。实验结果表明,Al/n+-gE样品通过400℃快速热退火(rTA)30 S表现出欧姆接触特性,并且接触电阻率ρC最低,为1.3x10-5Ω·CM2。

Germanium is used as the primary material on the micro-or opto-electronic devices,due to the much higher electron and hole mobility compared to Si,as well as its favorable absorption coefficient in the near infrared wavelength regime(1.3-1.5 μm).However,the ohmic contact formation on n-type Ge is still a challenge because of the severe Fermi level pinning effect of n-Ge and the low concentration of P-situ doping.Heavily-doped n-type Ge was achieved with phosphorus concentration of 1.5×1019cm-3 by the ion implantation.And then a series of Al/n+-Ge samples were prepared according to circular transmission line model(CTLM).The samples were annealed at different temperatures and with different annealing ways to analyze the contact characteristics.The test result indicate that the Al/n+-Ge contacts show ohmic characteristics by rapid thermal annealing(RTA) at 400 ℃ for 30 s,with the lowest contact resistivity ρc of 1.3×10-5 Ω·cm2.