GOALI: SiGe/Si Modulation-Doped Field-Effect Transistors for Low Power, High Speed Circuit Applications

近十年来，分子束外延（MBE）和超高真空化学气相沉积（UHV-CVD）技术在SiGe/ Si异质结构材料体系的外延生长方面取得了重大进展。SiGe/Si材料性能的显著改进带来了一种硅兼容技术，该技术有可能在特定应用设计中与III-V化合物半导体器件竞争，这些器件需要低功耗和高速，这是蜂窝电话和其他便携式和无线电子设备所需要的。这种材料体系在硅上实现的带隙工程为研究异质结双极晶体管（HBTs）和调制掺杂场效应晶体管（modfet）等器件提供了动力，这些器件迄今为止一直属于InP和GaAs领域。事实上，SiGe/Si hbt已经表现出优异的高频性能，其单位电流增益截止频率超过100 GHz。尽管理论预测表明，SiGe/Si modfet和相关器件（例如mosfet）应该具有与hbt相当或更好的性能，但该领域的实验工作基本上还处于初级阶段。为了评估其在先进的微波和数字电路中的实际用途，基于sige的场效应管需要深入发展。因此，PI提出的研究是由SiGe/Si材料增长的持续改进和开发可制造工艺的需要来推动的，以将这些材料转化为高性能的传统p型和n型modfet。这些器件也将使互补modfet的实现成为可能。在拟议的研究中，伊利诺伊大学（UIUC）和IBM将合作，显著推进低功耗、高速微波和数字电路应用所需的SiGe/Si modfet的生长和制造技术。本研究的目标是：1)为极低位错密度下SiGe/Si的生长提供新的见解；2)开发SiGe/Si异质结构上肖特基接触和欧姆接触形成的新方法；3)开发低损伤干刻蚀方法，用于SiGe在Si上的选择性刻蚀，反之亦然；4)研究短栅长（100 nm） p型、n型和互补型modfet的物理特性和性能；5)使用SiGe/Si modfet演示简单的微波和数字电路。* * *

9710418 Adesida Over the last decade, significant advances have been made in the epitaxial growth of SiGe/ Si heterostructure material system using molecular beam epitaxy (MBE) and ultra-high vacuum chemical vapor deposition (UHV-CVD). The significant improvements in SiGe/Si material properties have brought to fore a silicon-compatible technology that has the potential to compete favorably with III-V compound semiconductor devices in application-specific designs which require low power consumption and high speed which are needed for cellular telephones and other portable and wireless electronics. The bandgap engineering made possible on silicon by this material system has provided the impetus to study devices such as heterojunction bipolar transistors (HBTs) and modulation-doped field effect transistors (MODFETs) that have heretofore been in the domain of InP and GaAs. Indeed SiGe/Si HBTs have demonstrated excellent high frequency performance with unity current gain cut-off frequencies exceeding 100 GHz. Although, theoretical predictions have shown that SiGe/Si MODFETs and related devices (e.g. MOSFETs) should have comparable or better performance than those obtained for HBTs, experimental work in this area is essentially inchoate. SiGe-based FETs need intensive development in order to evaluate their practical usefulness for advanced microwave and digital circuits. The PI's proposed research is therefore motivated by the continued improvement in the growth of SiGe/Si materials and the need to develop manufacturable processes to turn these materials into high performance conventional p-type and n-type MODFETs. These devices will also make possible the realization of complementary MODFETs. In the proposed research, The University of Illinois (UIUC) and IBM will collaborate to significantly advance the growth and fabrication technologies for SiGe/Si MODFETs needed for low power, high speed microwave and digital circuit applications. The goals of the proposed research are 1) to provide n ew insights into the growth of SiGe/Si with very low density of dislocations; 2) to develop new methodologies for the formation of Schottky and ohmic contacts on SiGe/Si heterostructures; 3) to develop low damage dry etching methodologies for the selective etching of SiGe on Si and vice versa; 4) to study the physics and performance of short gate-length ( 100 nm) p-type, n-type, and complementary MODFETs; and 5) to demonstrate simple microwave and digital circuits using SiGe/Si MODFETs. ***