A new improved procedure for the determination of surface trap levels´ density using transverse acoustoelectric voltage measurements

A theoretical calculation of the acoustoelectric interaction in a semiconductor in which the additional effect of current density due to traps at the semiconductor/insulator interface was considered has recently been presented. Using this calculation, a modified procedure for the determination of interface or surface states´ density was developed, extending the use of TAV (transverse acoustoelectric voltage) versus applied bias V_B measurements to materials with high defect density. The experimental TAV_EX-V _B curve is compared with the theoretical expression of the TAV versus surface potential plot calculated assuming no interface traps. The difference between the two curves is attributed to the presence of interface traps. Measurements have been performed on Si and GaAs samples