High Speed Quarter Micron Buried-channel MESFETs With Improved Output Characteristics For Analog Applications

GaAs MESFET technology is based in large part upon ion-implantation into The substrates are rendered semi-insulating due semi-insulating substrates. to the presence of a large concentration of electrically active deep level defects which act to compensate the material. wafers the dominate deep level is EL2, and the EL2 associated family of 17 defects. It has been shown, however, that incorporation of greater than 10 donor atoms neutralizes the EL2 defect C11. Therefore, it should be possible to build devices which are essentially free of carrier trapping in the channel of MESFETs by these deep levels. However, carriers near the channelsubstrate interface will be subject to trapping since they can be scattered into the substrate and trapped by EL2 and other defects until they are thermally emitted. behavior of the device by changing the channel-substrate space charge distribution. Likewise, surface states or defects near the surface can trap carriers and influence device behavior. In nominally undoped GaAs