AlGaAs-GaAs HETEROJUNCTION MESFET WITH SELF-ALIGNED GATE
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
In semiconductor manufacturing technology, the heterojunction, modulation-doped AlGaAs-GaAs MESFET (metallized semiconductor field-effect transistor) shows promise as high speed logic devices because of the very high electron mobility in the channel. There have been high series resistance effects associated with these which degrade performance. This article proposes a way to alleviate this problem by obtaining a self-aligned gate requiring no implant/anneal. Fig. 1 illustrates the device with the layers being a semi-insulating substrate 6, an undoped GaAs 9, an undoped AlGaAs 8 and an N+ AlGaAs 7. A persistent drawback has been the high series resistance 3 associated with the source/drain regions and ohmic contact 2. The contact resistance is at 4, the heterojunction at 5, and the metal gate is shown as 1.