Characteristics and Breakdown Behaviors of Polysilicon Resistors for High Voltage Applications

Xiao-Yu Tang,Ke Dong

doi:10.1155/2015/423074

Abstract

With the rapid development of the power integrated circuit technology, polysilicon resistors have been widely used not only in traditional CMOS circuits, but also in the high voltage applications. However, there have been few detailed reports about the polysilicon resistors’ characteristics, like voltage and temperature coefficients and breakdown behaviors which are critical parameters of high voltage applications. In this study, we experimentally find that the resistance of the polysilicon resistor with a relatively low doping concentration shows negative voltage and temperature coefficients, while that of the polysilicon resistor with a high doping concentration has positive voltage and temperature coefficients. Moreover, from the experimental results of breakdown voltages of the polysilicon resistors, it could be deduced that the breakdown of polysilicon resistors is thermally rather than electrically induced. We also proposed to add an N-type well underneath the oxide to increase the breakdown voltage in the vertical direction when the substrate is P-type doped.

Highlights

With the booming market of power integrated circuits for the smart power management [1–4] and automotive and green energy, BCD [5, 6] (Bipolar-CMOS-DMOS) technology has been proved to be the best solution for these applications
In the high voltage application, the polysilicon resistor is still acting as an important device, there are few detailed reports about its properties, especially the voltage and temperature coefficients, under high voltages
The results show that the voltage and temperature coefficients strongly depend on the doping concentration

Summary

Introduction

With the booming market of power integrated circuits for the smart power management [1–4] and automotive and green energy, BCD [5, 6] (Bipolar-CMOS-DMOS) technology has been proved to be the best solution for these applications. Polysilicon [7] is supposed to be the best choice for integrated circuits technology due to its good and stable voltage and temperature coefficients. It has been experimentally observed that different doping concentrations in the polysilicon could lead to different voltage and temperature coefficients of the resistor [8–10]. Circuits for DC-DC and AC-DC applications in the smart power management system require the resistor to behave robustly under high voltages. This topic is not experimentally studied yet. We investigate the voltage and temperature coefficients of polysilicon resistors with different doping concentrations. After the high voltage stress, the resistance of the polysilicon could be degraded

Experimental

Results and Discussion

Conclusions

Conflict of Interests