We report the fabrication of high-electron-mobility Ge(111) n-MOSFETs using a novel and simple approach to passivate a Ge surface by rapid thermal oxidation (RTO). A thin interfacial GeO2 layer is formed by RTO, which passivates the high-κ /Ge interface. The GeO2-passivated n-MOSFETs fabricated using a gate-first self-aligned process with high-κ/metal gate demonstrate a high peak effective mobility (μeff∼713cm2ċV-1ċ -1 with ∼2× enhancement over control Si(100) devices. Moreover, at a drain bias of 1 V and at a gate overdrive of 1.2 V, Ge MOSFETs (L∼75μm) show a drive current of ∼1.1 mA/mm, which is ∼1.6× higher than that of the control Si devices. In addition, a good subthreshold slope of ∼130 mV/decade and an ION/IOFF ratio ∼103 were achieved using the GeO2 interfacial layer formed by RTO.
Bibliographical noteFunding Information:
Manuscript received July 14, 2010; revised August 12, 2010; accepted August 19, 2010. Date of publication October 7, 2010; date of current version October 22, 2010. This work was supported in part by the Defense Advanced Research Projects Agency and in part by the National Science Foundation under Grant 0618242. The review of this letter was arranged by Editor J. Cai.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering