Abstract: A novel buried n layer partial SOI RF power LDMOS is proposed.The output characteristics of the RF power LDMOS are greatly affected by the parasitic capacitance.Because the depletion width under the buried oxide layer of the proposed structure increases,the output capacitance decreases.Its drain-substrate capacitance is 39.1% and 26.5% less than that of the normal LDMOS and the partial SOI LDMOS respectively.At the 1dB compression point,its output power and power gain are 62% and 11.6% higher than those of the partial SOI LDMOS respectively,and the power-added efficiency of the proposed structure increases from 34.1% to 37.3%.The breakdown voltage of the proposed structure is 14% higher than that of the bulk structure.

Key words: PSOI, buried n layer, RF power LDMOS, output characteristics