Hiroshima University HV MOSFET Modeling with Hi SIMHV

Hiroshima University HV MOSFET Modeling with Hi. SIM_HV Benchmarks and New Developments Ehrenfried Seebacher, Mitiko Muira Matausch, Kund Molnar 2011 -09 -16

Hiroshima University & Presentation Overview HV Transistor Compact Modeling Requirements HV transistor sub-circuit modeling (the reference) State of the art HV Transistor Compact Models Hi. SIM_HV 1. x and 2. x • All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. • • • Benchmarking: DC, AC • Summary 2 © 2011

Hiroshima University & • • • 3 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. FOMs for HV Transistor Modeling RON (On Resistor) (high vgs, low vds, and temp. ) t s IDSAT (Saturation Current) ? a s e l s le t VT long & short a oce sib d l r s Cgg & Cgd Miller Cap u P po o e h t s Analog parameter for long channel length s a a l tr d e RF Parameter FT, FMAX ? d ns o o o go M m s de c a e p s © 2011

Hiroshima University & All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. HV CMOS Transistor Types Nwell PWELL Increased junction breakdown voltage (BV) of the drain diffusion is achieved by using a deep drain well PWELL Small on-resistance and high BV are contrary effects. NWELL The optimization of the tradeoff between both quantities is of major interest. The gate length is extended beyond the body-drain well junction, which increases the junction BV. The gate acts as a field plate to bends the electric field. RESURFeffect Quasi-Saturation Effect. 4 Nwell © 2011

All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Sub-circuit Modeling 5 © 2011

Hiroshima University & HV MOS Transistor Model Features: • Basic geometrical and process-related aspects such as oxide thickness, junction depth, effective channel length and width • RON modeling • Quasi saturation region and the saturation region • Geometry scaling, Short-channel effects • 1/f and thermal noise equation • Temperature Modeling for RON, VT, IDSAT • High Voltage Parasitic Models • Bulk (Substrate) current • Effects of doping profiles, substrate effect • 6 Modeling of weak, moderate and strong Model Limitations: • RF modeling • SH modeling • Cgd, Cgg …… • Graded channel • Impact ionization in the drift region • High-side switch (sub-circuit extension needed). © 2011 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Sub-circuit Model Features and Limitations

Hiroshima University & –Under development within the EU Project COMON “A Physics-Based Analytical Compact Model for the Drift Region of the HV-MOSFET” Antonios Bazigos, François Krummenacher, Jean-Michel Sallese, Matthias Bucher, Ehrenfried Seebacher, Werner Posch, Kund Molnár, and Mingchun Tang PSP HV – Transistor Model –In development based on PSP surface potential model MM 20 –asymmetrical, surface-potential-based LDMOS model, developed by NXP Research Hi. SIM_HV –CMC Standard model version 1. 1. 2 and 1. 2. 1 –Version 2. 0. 0 in evaluation 7 © 2011 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. State of the Art HV Compact Models and new Developments EKV HV Transistor

Hiroshima University & Extension of Bulk-MOSFET Model Hi. SIM 2 f. S 0 : at source edge f. SL : at the end of the gradual-channel approx. f. S(DL) : at drain edge (calculated from f. SL) Beyond Gradual-Channel Approximation l. Channel-Length Modulation l. Overlap Capacitance © 2011 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Complete Surface-Potential-Based Model

a few hundred volts > Bias Range > a few volts (Asymmetric) potential drop (Symmetric) Vgs, eff = Vgs – Ids x Rs Vds, eff = Vds – Ids x (Rs + Rdrift ) Vbs, eff = Vbs – Ids x Rs All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Hi. SIM-HV © 2011

Ndrift Vds Potential drop in the drift region Y. Oritsuki et al. , IEEE TED, 57, p. 2671, 2010. DDP V Y. Oritsuki et al. , IEEE TED, 57, p. 2671, 2010. 11 © 2011 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Consistent Modeling in Drift Region Ldrift

f. S(DL) VV DDP f. S(DL) : potential determining 　LDMOS characteristics HV Vgs [V] HV Vds [V] Hi. SIM reproduces f. S(DL) calculated by 2 D-device simulator. 12 © 2011 f. S(DL) [V] All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. f. S(DL) [V] Hiroshima University & Key Potential Values

Hi. SIM_HV 1. 0. 0 Series Bias Dependence is modeled based on principle. Y. Oritsuki et al. , IEEE TED, 57, p. 2671, 2010. All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Modeling of Rdrift © 2011

Id [A] Vgs=7. 5 V Accuracy Comparison of Ids-Vds : 2 D-Device Simulation Results : Hi. SIM-HV Results Vgs=10 V Vgs=5 V Vgs=2. 5 V Quasi-saturation behavior of LDMOS is reproduced. 14 © 2011 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. gd [S] Hiroshima University &

Relatively High Breakdown Voltage All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Current-Voltage Characteristics Relatively Low Breakdown Voltage © 2011

Ids - Vgs Gm vs. Vgs Care must be taken when adjusting critical parameters describing the Vgs dependence. © 2011 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Empirical Model: Issues

17 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hi. SIM_HV 1. 1. 2 v. BSIM 3 v 3 Subcircuit Hiroshima University & Model Benchmark Output Characteristic © 2011

Capacitance [f. F] 2. 0 0. 8 Cgg 1. 8 1. 2 Cgb -4 -2 Cgd Vds=0 V Cgs 0. 4 0 Vgs [V] 2 Normal MOSFET Asymmetrical LDMOS Symmetrical HVMOS 4 Vgs [V] All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Capacitance [f. F] Hiroshima University & Capacitance-Voltage Characteristics © 2011

BSIM 3+JFETS Subckt. • Subcircuit: bad fitting quality, especially in accumulation. • Hi. SIM_HV: good fitting quality in all regions. 19 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & AC Modeling: Cgg Hi. SIM_HV © 2011

All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Self-Heating Effect for DC Analysis © 2011

RC-Network: All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Self-Heating Effect for AC Analysis © 2011

Hi. SIM_HV 2. 0. 0 Series MOSFET + Resistor DP Channel MOSFET Resistor 22 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Modeling Rdrift © 2011

Node potential Vddp is solved iteratively. All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & © 2011

VDDP Velocity saturation affects strongly on I-V characteristics. 24 © 2011 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Iddp Hiroshima University & I-V Characteristics of Resistor 2 D-Device Simulation

Lover Wdep Djunc W 0 xdep xov xjunc xdep Vddp xjunc Djunc : junction depth : current exude coefficient into A depletion region 25 © 2011 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Modeling Current-Flow in Overlap Region

Hiroshima University & 2 D-Device Sim. Hi. SIM_HV Vds = 0. 5 V, 2 V, 5 V, 10~30 V xov improvements The xov model enables to fit I-V characteristics for wide range of bias conditions. Id [m. A] Vgs [V] Id [m. A] (Lch = 1 mm , Lover = 1 mm, Djunc = 2 mm) Vgs= 3~9 V, 15 V, 30 V Vds [V] All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Verification of I-V Characteristics Vds = 0. 5 V, 2 V, 5 V, 10~30 V Vgs [V] Vgs= 3~9 V, 15 V, 30 V Vds [V] 27 © 2011

Hi. SIM_HV 1. x. x Old Empirical Hi. SIM_HV 2. x. x New Physical Ids - Vgs Gm vs. Vgs All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Empirical Model vs. Physical Model: Id. Vg © 2011

Hi. SIM_HV 1. x. x Old Empirical Hi. SIM_HV 2. x. x New Physical All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Empirical Model vs. Physical Model: Id. Vd © 2011

All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hiroshima University & Hi. SIM_HV Release © 2011

Hiroshima University & The Extreme Case; 120 V Transistors HV NMOS output and transfer characteristic of a typical wafer. W/L=40/0. 5, VGS= 2. 9, 4. 8, 6. 7, 8. 6, 10. 5, 12. 4, 14. 3, 16. 2, 18. 1, 20 V, VBS=0 V. & VBS= 0, -1, -2, -3, -4 V, VDS=0. 1 V. + = measured, full lines= BSIM 3 v 3 model; dashed lines = Hi. SIM_HV 1. 2. 1 31 © 2011 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Hi. SIM_HV 1. 2. 1 v. BSIM 3 sub-circuit

Hiroshima University & Isolated HVMOS: High-Side Switch Modeling - HVMOS used on the low-side of a load: All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Source and Substrate hold at the same potential - HVMOS used on the high-side of a load: Both Source and Drain can be placed at high potential => Ron is changing with Vsub-s Transfer Characteristics Vsub=0 Vsub=120 V Vd=0. 1 V, Vs=Vb=0 Hi. SIM_HV 1. 2. 1: Vsub modulates the effective depth of the drift region: Rdrift(Vsub, s) 32 © 2011

Hiroshima University & Hi. SIM_HV All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. The following effects are also Complete Surface potential-based: included: Hi. SIM_HV solves the Poisson equation along the MOSFET • Depletion effect of the gate channel iteratively, polycrystalline silicon (poly-Si). including the resistance effect in the drift region. • Quantum mechanical • CLM high flexibility • Narrow channel 20 model flags • STI scales with the gate width, • Leakage currents the gate length, (gate, substrate and gate-induced the number of gate fingers drain leakage (GIDL) currents). and the drift region length. • Source/bulk and drain/bulk diode In addition, Hi. SIM_HV is capable of modeling models. symmetric and asymmetric HV devices. • Noise models (1/f, thermal noise, induced gate noise). • Non-quasi static (NQS) model. © 2011 33

Summary 34 All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. Decision for HV Model depends very much on the application Sub-circuit approach is very flexible and usable for switching applications and for analog applications using large transistors sizes. Hi. SIM_HV 1. 1. 2 and 1. 2. 1 shows high accuracy for all benchmarks. Detailed know how in parameter extraction needed Extensive measurements necessary. Hi. SIM_HV 2. x First Version New physical drift region model is under evaluation and shows excellent benchmark results. © 2011

All rights reserved. © 2011 · austriamicrosystems AG. Material may not be reproduced without written approval of austriamicrosystems and may only be used for noncommercial educational purposes at the “University of Technology Graz”. - analog experts to help you leap ahead © 2011