High-transconductance self aligned GaAs MESFET using implantation through an AlN layer

Extremely thin channel layers formed by implantation through an AlN layer are used in fabricating high-transconductance self-aligned GaAs MESFETs. The transconductance is found to reach its maximum at 300 mS/mm. The uniformity of the threshold voltage of the FETs is such as to be satisfactory for application to LSIs. The results indicate that the high-transconductance self-aligned GaAs MESFETs fabricated by the through-AlN implantation technique hold considerable promise for use in ultra-high-speed GaAs VLSIs. A graph is included giving the K-values of through-implanted and conventional implanted FETs as a function of the threshold voltage.