Enhanced ESD-Capability of High-Voltage 32 V N-Channel LDMOSs with the Body-Side Hetero-Junction Structure

As electronics become lighter, shorter and more complex, the potential damage to integrated circuits (ICs) from electrostatic discharge (ESD) becomes more severe. In many applications, high voltages will result in high electric fields and high current densities in miniaturized components, which can lead to gate oxide breakdown of circuit components and thermal damage in ICs. Therefore, ESD protection circuits are added inside the electronic product in order to prevent the above damage, but the area of the protection cell should not be too large, otherwise a large proportion of the IC manufacturing cost is spent on the protection circuit. In this paper, we investigate how to improve the ESD protection of the designed high-voltage components through TSMC’s 0. 1S-micron BCD HV process. The sample structures of this work all use high-voltage N-channel laterally diffused MOSFETs (LDMOS), and the I/O protection components can be improved by this protection architecture. First, the ESD robustness of the device is enhanced by embedding a Schottky diode in the bulk end of the nLDMOS. The Schottky diode is parasitized horizontally at the body terminal. Since the parasitic Schottky diode is at the body electrode of the device, the parasitic BJT capability is enhanced, making it easier to trigger the conductivity of the device. Therefore, the new components $\mathrm{V}_{\mathrm{t}i}$ and $\mathrm{V}_{\mathrm{h}}$ values decrease (because the horizontal parasitic Schottky is reversed so the decreasing is obvious), so that the high-voltage ESD protection components have a better performance under ESD events, this design also makes the anti-ESD capacity $\mathrm{I}_{\mathrm{t}2}$ significantly increased. In the case of the body-end horizontal (reversed) embedded Schottky element, the largest $\mathrm{I}_{\mathrm{t}2}$ is found on the $\mathrm{R}\mathrm{e}\mathrm{f}_{-}8\mathrm{S}_{-}\mathrm{B}_{-}8$ device, whose $\mathrm{I}_{\mathrm{t}2}$ improvement rises up to 4. 529A, an significant increase of 244.41% was achieved as compared with the reference sample.