Research And Design For A Novel 700V LDMOS With Low Specific On-resistance

The 700 V high voltage LDMOS?Lateral Double-diffused metal oxide semiconductor field effect transistor?can be widely applied to AC-DC,class-D amplifier,power management and other high voltage integration circuit because of the compatibility with CMOS and BCD process.For the 700 V LDMOS,The R_on,sp with the increase of breakdown voltage?BV?,and the power consumption of the power device will increase.Obviously it violates the policy of energy conservation and emission reduction.Therefore,improving the BV and reducing the low R_on,sp of LDMOS are hot research topics for the domestics and overseas.A novel high voltage LDMOS with low R_on,sp has been proposed in this paper.Linear variable doping?LVD?profile technology is introduced compared with conventional triple RESURF LDMOS with?n-type top?N-top layer.The LVD profile technology will optimize the surface electric field distribution and contribute to a higher BV.Furthermore,the LVD N-top layer also introduces much more major carriers in surface conduction path and reduces the R_on,sp of the novel device.The initial doping concentration,the gradient and the position of LVD N-top layer have been optimized by Medici.The optimized novel high voltage LDMOS with LVD N-top layer obtains a high BV of 847 V,a low R_on,sp of 79.08 m?·cm² and a high figure of merit of 9.08 MW/cm².Compared with conventional device,the performance of novel high voltage LDMOS with LVD N-top layer has achieved a qualitative improvement.A feasible process flow to produce the novel high voltage LDMOS with LVD N-top layer has also been given.In addition,the analytical silicon limit model under different temperature of conventional high voltage LDMOS with N-top layer is derived.Base on 5.93×10^-6×?×BV^? which is conventional triple RESURF silicon limit model between R_on,sp and BV,the expression of a have been derived under different temperature when ? = 11/6 and ? = 2 respectively.The analytical silicon limit model R_on,sp = 5.93×10^-6×22.54?T/300?^1.478×BV² under different temperature when ? = 2 is in good agreement with the experimental results and break the conventional silicon limit of conventional triple RESURF technology.