Abstract:

Ar ion beams with the energy of 550 eV were used to bombard the backside of n·MOSFET chip to im-prove the direct current characteristics and overcome the low-frequency noise of the device in the saturation region.The direct curent characteristics include the following aspects:the transconductance,the threshold voltage and the effective mobility of the surface inversion layer cartier.The results indicate that,as the bombardment time increa-ses,the transconductance and the efective mobility first increase and then decrease,while the change tendency of the threshold voltage is on the contrary.Th e low-frequency noise obviously decreases after the bombardment.It is proved by experiments that all these changes are due to the trap density variation on the Si- siO₂ surface and the fixed charge density variation in SiO₂.

Key words: backsurface Ar bombardment, MOSFET, transconductance, threshold voltage, noise