Effect of p-Type Buried Layer Dose on Hot Carrier Degradation of RONin 700 V Triple RESURF nLDMOS

Abstract

The degradation of ON-resistance ( $R_{\mathrm{\scriptscriptstyle ON}})$ caused by the hot-carrier injection in the 700 V triple reduce SURface field LDMOS is investigated in this letter. Experimental results show that the degradation of $R_{\mathrm{\scriptscriptstyle ON}}$ is reduced by increasing the dose of p-type buried layer (Pbury). The average $\text{R}_{\mathbf {on}}$ shift is only 3.7% after 168 h of aging tests with Pbury dose equal to 3.4 $\times 10^{12}$ cm $^{\mathrm {-2}}$ . Both peak electric field and impact ionization rate near the bird’s beak close to the source are decreased by increasing the dose of Pbury. Meanwhile, the peak electric field close to the drain is increased to avoid the drop in the breakdown voltage.