Reduction of Parasitic Delays in Nitrides-based Transistors
Abstract
In this project, we have demonstrated five new approaches to reduce the access resistances in GaN HEMTs in order to improve their RF performance. The first approach is based on strain engineering. Additive tensile biaxial strain has been introduced into an AlGaN/GaN hetero-structure grown on a Si wafer by reducing the thickness of the Si substrate after the growth of the nitride epilayer. As a result, the electron sheet density increases by ~25% and reaches ns~1x1013 cm-2. This intrinsic piezoelectric-induced doping allows decreasing the access resistance of AlGaN/GaN HEMTs. This new substrate-etching technology has been used to increase the on-current in the linear region and the current density of AlGaN/GaN transistors grown on silicon by 27%. of the lowest contact resistance reported in the AlGaN/GaN literature. A second technology to reduce the contact resistance is based on the top-down fabrication of AlGaN/GaN nano-ribbons to allow the ohmic metal to contact the 2DEG directly. Lower Rc is observed in AlGaN/GaN NRs compared to the conventional planar device.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 09, 2010
- Accession Number
- ADA530594
Entities
People
- Brandon Lu
- D. S. Lee
- Hwang Sheng Lee
- J. W. Chung
- M. Azize
- Tomás Palacios
Organizations
- Massachusetts Institute of Technology