金属与半导体Ge欧姆接触制备、性质及其机理分析  

Properties and mechanism analysis of metal/Ge ohmic contact

作　　者：严光明[1] 李成[1] 汤梦饶[1] 黄诗浩[1] 王尘[1] 卢卫芳[1] 黄巍[1] 赖虹凯[1] 陈松岩[1] 

机构地区：[1]厦门大学物理学系半导体光子学研究中心,厦门361005

出　　处：《物理学报》2013年第16期344-348,共5页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2012CB933503;2013CB632103);国家自然科学基金(批准号:61036003;61176092);中央高校基本科研业务费(批准号:2010121056)资助的课题~~

摘　　要：金属与Ge材料接触时界面处存在着强烈的费米钉扎效应,尤其与n型Ge形成的欧姆接触的比接触电阻率高,是制约Si基Ge器件性能的关键因素之一.本文对比了分别采用金属Al和Ni与Si衬底上外延生长的p型Ge和n型Ge材料的接触特性.发现在相同的较高掺杂条件下,NiGe与n型Ge可形成良好的欧姆接触,其比接触电阻率较Al接触降低了一个数量级,掺P浓度为2×1019cm-3时达到1.43×10-5·cm2.NiGe与p型Ge接触和Al接触的比接触电阻率相当,掺B浓度为4.2×1018cm-3时达到1.68×10-5·cm2.NiGe与n型Ge接触和Al电极相比较,在形成NiGe过程中,P杂质在界面处的偏析是其接触电阻率降低的主要原因.采用NiGe作为Ge的接触电极在目前是合适的选择.Large contact resistance due to Fermi level pinning effect at the interface between metal and n-type Ge strongly restricts the performance of Ge device on Si substrate. In this paper, the contacts of metal A1 and Ni with n-type Ge and p-type Ge epitaxial layers grown by UHV/CVD are comparatively studied. It is found that the contact of NiGe/n-Ge is better than that of Al/n-Ge at the same dopant concentration. When the concentration of P is 2 × 10^19 cm-3, the ohmic contact of NiGe/n-Ge with Pc down to 1.43× 10-5 Ω2.cm2 is demomstrated, which is about one order of magnitude lower than that of A1/n-Ge contact. The specific contact resistance of NiGe/p-Ge is 1.68 × 10-5.cm2 when the B concentration is 4.2 × 10^18 cm-3, corresponding to that of Al/p-Ge. Compared with A1/n-Ge contact, P segregation at the interface between NiGe and Ge, rather than lowering Schottky barrier height, is the main reseaon for achieving the low specific contact resistance. NiGe/Ge contact should be a good choice for contact electrode for Ge devices at present.

关 键 词：金属与Ge接触性质 NiGe 比接触电阻率 

分 类 号：TN386.1[电子电信—物理电子学]