GOALI: RF Performance of Si-Based RITD for Mixed-Signal Applications

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

0323657 Berger The drive to develop advanced semiconductor devices and circuits is fueled by the wealth of electronic and optical properties of heterostructures made possible by band structure engineering. Tunnel diodes (TD) can be integrated with transistors to create novel quantum nonlinear functional devices and circuits due to the unique property of a tunnel diode's negative differential resistance (NDR). Such integrated circuits have demonstrated enhanced performances in circuit speed, reduce component count and lower power consumption. Previous circuit work incorporating TDs, at places like Motorola Laboratories, has been limited to III-V compound semiconductors only. However, until recently, it was not practical to translate this to the low-cost and high production volume Si world. But recent developments in Si-based TD technology by the PI and other researchers are challenging this roadblock. One aim of this proposal is to seek ways to integrate Si-based resonant interband tunnel diodes (RITD) with Si/SiGe transistors to meet the challenges in the wireless communications by transferring this III-V-based TD circuit technology to Si. The PI seeks to capitalize upon recent DC performance milestones achieved within his laboratory on Si-based RITDs, namely peak-to-valley current ratio (PVCR) up to 3.8 at room temperature or peak current densities Jp exceeding 150 kA/cm 2 . This project aims to boost Si wireless capabilities that could eventually lead to an entire radio on a single Si chip or other interesting fusions of digital and analog circuits. Further, tunnel diodes have been shown to be very radiation hard and were used extensively in some of the first communication satellites in the 1960's, thus lending their introduction into military and non-terrestrial applications as well. Partnering with Motorola Laboratories in the form of a Grant Opportunities of Academia in Liaison with Industry (GOALI) is testimony to the level of interest and curiosity of industry to explore this technological pathway further, before embracing it. Motorola is willing to share their circuit and system experience as well as apply their in-house analog modeling of these nonlinear Si/SiGe TDs. This project will provide an environment where students can be trained in a broader perspective of the research process, from device physics, material and device processing, to device and circuit testing and modeling. Collaborative efforts required in this project will allow graduate and undergraduate students not only to have natural exchange and supervision with PIs, but also to have strong interactions with scientists in government and industry research laboratories, which will facilitate their acquisition of knowledge and provide an initial research experience that promotes the notion of teaming in their future careers. At Ohio State (Berger), undergraduate research is expected to play a large component in the proposed research. Discussions have already commenced with the EE Honors Program representative and the PI to ramp up towards a collective REU Site submission in Fall 2003. In lieu of this, the PI will submit requests for REU supplements as well as the REU Site request. The PI has a long and established history of using undergraduate researchers through REU supplements. Recruitment of underrepresented peoples has been and will be a facet in the PIs research projects. The technical merits of this project derive from its impact on (i) increase circuit speed due to shortened path lengths and increased functionality, (ii) reduce component count (more computational power per unit area), (iii) lower power consumption (fewer components per logic function), (iv) compact the layout using 3-D integration of tunnel diodes above/below transistors, and (v) extend RF wireless technology.