The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 28, 2009
Filed:
Sep. 29, 2005
Umesh K. Mishra, Montecito, CA (US);
Huili Xing, South Bend, IN (US);
Debdeep Jena, South Bend, IN (US);
Siddharth Rajan, Goleta, CA (US);
Umesh K. Mishra, Montecito, CA (US);
Huili Xing, South Bend, IN (US);
Debdeep Jena, South Bend, IN (US);
Siddharth Rajan, Goleta, CA (US);
The Regents of the University of California, Oakland, CA (US);
Abstract
Novel GaN/AlGaN metal-semiconductor field-effect transistor (MESFET) structures grown without any impurity doping in the channel. A high-mobility polarization-induced bulk channel charge is created by grading the channel region linearly from GaN to AlGaN over a distance, e.g., 1000 Å. A polarization-doped field effect transistor (PolFET) was fabricated and tested under DC and RF conditions. A current density of 850 mA/mm and transconductance of 93 mS/mm was observed under DC conditions. Small-signal characterization of 0.7 μm gate length devices had a cutoff frequency, f=19 GHz, and a maximum oscillation of f=46 GHz. The PolFETs perform better than comparable MESFETs with impurity-doped channels, and are suitable for high microwave power applications. An important advantage of these devices over AlGaN/GaN HEMTs is that the transconductance vs. gate voltage profile can be tailored by compositional grading for better large-signal linearity.