Authors: R.S. Saxena, M.J. Kumar
Affilation: Indian Institute of Technology, New Delhi, India
Pages: 602 - 604
Keywords: strained Si, SiGe, trench gate, dual gate, power MOSFET, compositionally graded SiGe buffer
We propose a new dual gate trench power MOSFET with strained Si channel that not only provides lower on resistance than the conventional trench MOSFET but also enables the in-circuit configurability of its characteristics for optimized circuit applications. In the proposed structure, we have split the gate of a conventional trench MOSFET structure into two parts. In the resulting structure, one of the two gates controls the inversion charge of the channel whereas the other gate controls the accumulation charge in the drift region. Using 20% Ge mole fraction in the SiGe body with compositionally graded SiGe buffer in the drift region enables us to create the strain in the channel along with the graded strain in accumulation region. As a result, the proposed structure exhibits 10% enhancement in current drivability, 20% reduction in the on-resistance, 17% reduction in the switching delays and 72% improvement in peak transconductance at the cost of only 12% reduction in the breakdown voltage when compared to conventional trench gate MOSFET. We have also shown that the flexibility of applying suitable different bias voltages at the two gates may significantly improve device performance.
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