GOALI: Germanium-on-insulator tunneling transistors

本研究的目的是研究一种与主流硅技术兼容的新型半导体器件——在外延绝缘体上锗通道中制造的隧道晶体管。原则上，这些器件不受标准场效应晶体管的亚阈值摆幅限制，因此有可能在室温下获得大的开/关电流比，同时降低电源电压，从而降低大型集成电路的功耗。实现方法包括使用超薄单晶绝缘体上的锗通道与晶格匹配的外延高介电体相结合，所有这些都生长在硅衬底上。知识优势：虽然硅基隧道晶体管是当前工业研究的一个主题，但绝缘体上的锗器件既未被探索，也很有前途，因为较小的Ge带隙意味着在相同的电源电压下具有更高的隧道电流，而电流驱动是缩小晶体管的关键指标，隧道或场效应将决定未来器件的缩小程度。隧道晶体管的另一个有趣的方面是，它们可以完全免除反转通道，大大减少电容，这可能证明对高速模拟放大器感兴趣。采用全外延绝缘体上Ge异质结构制造的平面横向隧道晶体管，无论有无反转通道，将由IBM-Brown联合研究团队进行研究，该团队在Ge器件方面具有互补的专业知识和现有的密切合作。更广泛的影响：与标准场效应器件相比，拟议的研究将衡量基于锗的隧道晶体管的技术潜力。替代通道材料的插入，如Ge，是硅技术路线图的关键部分。要研究的替代隧道器件保持超大规模集成电路的兼容性和室温操作，使它们适用于混合电子电路。拟议的研究将对教育产生影响，布朗大学的研究生将与IBM研究所密切互动（包括暑期实习），本科生将获得研究经验，包括通过布朗MRSEC确定的少数族裔机构的本科生，该机构有一个重点推广计划。

The objective of the proposed research is to investigate a new class of semiconductor devices compatible with dominant silicon technology -- tunneling transistors fabricated in epitaxial germanium-on-insulator channels. These devices are not constrained, in principle, by the subthreshold swing limit of standard field effect transistors, so there is the potential of obtaining large on/off current ratios at room temperature while reducing the power supply voltage and hence the power consumption of large integrated circuits. The enabling approach involves the use of ultrathin single-crystal germanium-on-insulator channels combined with lattice-matched epitaxial high- dielectrics, all grown on silicon substrates. Intellectual merit: Although silicon-based tunneling transistors are a topic of current research in industry, germanium-on-insulator devices are both unexplored and promising, because the smaller Ge bandgap promises orders of magnitude higher tunneling current at the same power supply voltage and current drive is a key metric for downscaled transistors, tunneling or field-effect, that will determine how much device scaling will help in the future. Another interesting aspect of tunneling transistors is that they can dispense with the inversion channel altogether, greatly reducing the capacitance, which may prove of interest for high-speed analog amplifiers. Planar lateral tunneling transistors, with and without an inversion channel, fabricated in all-epitaxial Ge-on-insulator heterostructures will be studied by the combined IBM-Brown research team, which has complementary expertise and an existing close co-PI collaboration on Ge devices. Broader Impact: The proposed research will gauge the technological potential of germanium-based tunneling transistors compared to standard field-effect devices. The insertion of alternative channel materials, such as Ge, is a key part of the silicon technology roadmap. The alternative tunneling devices to be studied maintain VLSI compatibility and room temperature operation, making them viable for hybrid electronic circuits. The proposed research will have an educational impact, with Brown graduate students interacting closely with IBM Research (including summer internships), and undergraduates gaining research experience, including undergraduates from minority institutions identified through the Brown MRSEC, which has a focused outreach program.