Hetero MIS Structure Using Ultra High Mobility Semiconductor

这项工作的目的是证明锑化铟（InSb）在21世纪半导体材料的有用性，当器件尺寸的减小，当前集成电路改进的主要动力，将由于各种尺寸效应而失去其优势。我们指出碲化镉(CdTe)/InSb异质结构在77K时可以认为是MIS结构，因为它们具有相同的晶格常数，CdTe的能隙宽达1.6eV， InSb的能隙宽达0.23eV。CdTe/InSb异质结构在77K时的能带图与SiO_2/Si体系在室温下的能带图非常相似。我们用真空MOCVD法在InSb上生长了CdTe。采用DMCd气体作为Cd源，在反应器入口处以670 C裂解DET。在低至250℃的衬底温度下生长单晶CdTe。通过C-V测量证实，该异质结构在77K时作为MIS结构运行。采用MBE法制备了较好的CdTe/InSb异质结构。单晶碲化镉薄膜在207 ~ 243℃的衬底温度下生长，表面光滑。该异质结构具有良好的MIS特性。实验结果表明，衬底温度在240℃左右是最佳的。首次采用MBE生长的CdTe/InSb异质结构制备了InSb MIS晶体管，并成功运行。场效应迁移率为1200cm^2/Vs。通过在衬底和碲化镉之间添加一个MBE生长的InSb缓冲层，性能将大大提高。

Aim of this work is to demonstrate an usefulness of Indium Antimonide (InSb) for semiconductor materials in the 21 century, when reduction of device size, the dominant motive force of the present improvement in integrated circuits, will loss its advantage due to various size effects.We have pointed out the Cadmium Telluride (CdTe)/InSb hetero structure can be considered as MIS structure at 77K, since they have the same lattice constant and energy gap of CdTe is as wide as 1.6eV while that of InSb as 0.23eV at 77K. The band diagram of the CdTe/InSb hetero structure at 77K is very similar to that of the SiO_2/Si system at room temperature if we normalized them by thermal energy.We have grown CdTe on InSb by vacuum MOCVD method. DET was cracked at 670ﾟC just at the inlet of the reactor, while DMCd gas was used as the Cd source. Single crystal CdTe was grown at substrate temperatures as low as 250ﾟC. This hetero structure has been confirmed, by C-V measurement, to operate as MIS structure at 77K.MBE method has be used for growing better CdTe/InSb hetero structure. Single crystal CdTe films have been grown at substrate temperatures between 207 and 243ﾟC with smooth surface. This hetero structure showed good MIS characteristics. It was found that the best substrate temperature is about 240ﾟC.InSb MIS transistors using MBE grown CdTe/InSb hetero structure have been fabricated, for the first time, and it was operated successfully. The field effect mobility was 1200cm^2/Vs. The performance will be improved drastically by adding an MBE grown InSb buffer layer between the substeate and CdTe.