Self-Organized Ge Nanospherical Gate/SiO<sub>2</sub>/Si<sub>0.15</sub>Ge<sub>0.85</sub>–Nanosheet n-FETs Featuring High ON-OFF Drain Current Ratio
oleh: Po-Hsiang Liao, Kang-Ping Peng, Horng-Chih Lin, Thomas George, Pei-Wen Li
| Format: | Article |
|---|---|
| Diterbitkan: | IEEE 2019-01-01 |
Deskripsi
We reported experimental fabrication and characterization of Si<sub>0.15</sub>Ge<sub>0.85</sub> n-MOSFETs comprising a gate-stacking heterostructure of Ge-nanospherical gate/SiO<sub>2</sub>/Si<sub>0.15</sub>Ge<sub>0.85</sub>-nanosheet on SOI (100) substrate in a self-organization approach. This unique gate-stacking heterostructure is simultaneously produced in a single oxidation step as a consequence of an exquisitely controlled dynamic balance between the concentrations of oxygen, Si, and Ge interstitials at 900 °C. Process-controlled tunability of nanospherical gate of 60-100 nm in diameter, gate oxide thickness of 3 nm, and Si<sub>0.15</sub>Ge<sub>0.85</sub> nanosheet with compressive strain of -2.5% was achieved. Superior gate modulation is evidenced by subthreshold slope of 150 mV/dec and I<sub>ON</sub>/I<sub>OFF</sub> > 5 × 10<sup>8</sup> (I<sub>OFF</sub> <; 10<sup>-6</sup> μA/μm and I<sub>ON</sub> > 500 μA/μm) measured at V<sub>G</sub>= +1V , V<sub>D</sub> = +1 V, and T = 80 K for our device with channel length of 75 nm.