Complete Surface-Potential Modeling Approach Implemented in the HiSIM Compact Model Family for Any MOSFET Type

Transcription

1 Complete Surface-Potential Modeling Approach Implemented in the HiSIM Compact Model Family for Any MOSFET Type WCM in Boston 15. June, 2011 M. Miura-Mattausch, M. Miyake, H. Kikuchihara, U. Feldmann and H. J. Mattausch HiSIM Team, Hiroshima University HiSIM 1

2 Basic Device Equations s Gradual-Channel Approximation Charge-Sheet Approximation reduced to surface potential φ s HiSIM 2

3 Property of Surface-Potential Model Q(φ) = ν = μ E: velocity : mobility The surface potential consistently determines charges, capacitances and currents under all operating conditions. HiSIM 3

4 Relationship among Device Properties (at drain side) (at source side) HiSIM 4

5 Specific Feature of Surface-potential Model one equation for all bias conditions HiSIM 5

6 Model Extraction for 45nm Technology W g /L g =2μm/200nm W g /L g =2μm/40nm Measurement HiSIM2 one model for any device sizes without binning HiSIM 6

7 Current Derivatives for 45nm Technology Measurement HiSIM W g /L g = 2μm/40nm Beyond the 45nm generation nonphysical effects are getting obvious. HiSIM 7

8 Universal Mobility V ds =0.1V impurity concentration carrier concentration carrier mobility HiSIM 8

9 Requirements for RF Applications Harmonic Distortions Non-Quasi-Static Effect Noise Characteristics HiSIM 9

10 Feature of Potential-Based Model Current Equation: I = qnμe All physical quantities are function of surface potentials. Solution of Poisson s Equation Important RF characteristics are originated by the potential distribution along the channel. I-V characteristics reflect all important RF properties. Accurate parameter extraction for I-V characteristics is important. S. Matsumoto et al., IEIEC T E, E88-C, p. 247, S. Hosokawa et al., Ext. Abs. SSDM, pp. 20, M. Miura-Mattausch et al., IEEE TED, HiSIM 10

11 Descendant of MOSFET MG-MOSFET SOTB-MOSFET TFT SOI-MOSFET MOSFET HV-MOSFET MOS-Varactor IGBT HiSIM 11

12 HiSIM Family Bulk-MOSFET HiSIM2 High-Voltage MOSFET HiSIM_HV SOI MOSFET HiSIM-SOI Thin-Film Transistor Double-Gate MOSFET Insulated-Gate Bipolar Transistor HiSIM-TFT HiSIM-DG HiSIM-IGBT HiSIM 12

13 SOI-MOSFET Modeling many possible conditions Si Si substrate HiSIM 13

14 Poisson s Equation + Gauss s Law V φ φ gs fb s,soi b,soi s,soi Q+Q + Q + Q - V = φ - CFOX Qs,bulk = φs,bulk - CBOX 1 Q s,bulk + Qdep = φ 2 b,soi - C i dep b,soi s,bulk SOI Three surface potentials are solved simultaneously by iteration. Q b,soi φ b.soi φ s.soi Calculation results HiSIM 14

15 Smooth Transition among Conditions T SOI T BOX Conditi on Device PD Device DD Device DD Device FD HiSIM 15

16 C-V Characteristics T SOI =150nm T BOX =110nm : HiSIM-SOI : 2D-Device Sim. T SOI =50nm T BOX =110nm T SOI =50nm T BOX =50nm DEVICE1 DEVICE2 T SOI =25nm T BOX =110nm DEVICE3 DEVICE4 HiSIM 16

17 Potential Distribution in Thin-Body MOSFET device surface insulator Back surface potential is strongly dependent on T SOI. Consistent solution of Poisson s equation HiSIM 17

18 Device 4: Thin-Body SOI-MOSFET back-gate bias V bs dependence V bs φ b.soi φ s.soi HiSIM 18

19 Floating-Body Effect φ b.soi is unstable. symbol: 2D-Sim. line: HiSIM-SOI SOI bulk φ s.bulk φ b.soi φ s.soi BOX φ b.soi reduction change from FD to PD HiSIM 19

20 Charge Accumulation Impact Ionization: Include accumulation charge in the Poisson equation Increase the surface potential φ s0.soi Increase the inversion charge Q i according to V ds increase HiSIM 20

21 History Effect Transient Characteristics of the Floating-Body Effect Τ d : Time constant of Q h accumulation T d H. Toda et al., SSDM HiSIM 21

22 I d -V d Comparison with Measurements gds gds gds V sub = 0.0V V sub = 0.0V V sub = 0.0V V sub = 0.0V V sub = -1.5V V sub = -1.5V V sub = -1.5V V sub = -1.5V measurement HiSIM-SOI HiSIM 22

23 I d -V d Characteristics as a function of N SOI W g =0.25mm, L g =0.15mm N SOI (cm -3 ) = 1.0e16 2.0e16 5.0e16 Vds Vds Vds Vds Vds Vds Ids Ids Ids Ids Ids Ids Ids 1.0e17 2.0e17 5.0e17 Ids Ids 1.0e18 2.0e18 5.0e18 Vds Vds Vds enhanced floating body effect with increased N SOI HiSIM 23

24 Scalability Tests V th vs. N SOI for various V bs 0.6 V ds =0.05V, W g =10μm, L g =0.15 μm Threshold Voltage (V) Vsub = 0 to -3V step -1.0V e16 1.0e17 1.0e18 1.0e19 N SOI (cm -3 ) automatic FD PD shift HiSIM 24

25 HiSIM-SOI - Considering all possible induced charges in the Poisson equation - Solving the Poisson equation iteratively - Deriving accurate analytical solution as initial values Solving the Poisson equation in a consistent way is only a possibility to model all different structures and conditions within one model framework. HiSIM 25

26 carrier concentration T si =10nm gate gate HiSIM-DG V gs =1V V ds =0V T si T si =20nm gate gate T si =40nm gate gate T si Body potential is floating. The floating body potential makes modeling difficult. HiSIM 26

27 Potential Dependence on T si and N sub N sub T Si φ s0 (V) φ s0 (V) HiSIM 27

28 C-V Characteristics Reduction of T si has only a small influence on the capacitance characteristics. HiSIM 28

29 Carrier Traps in TFT Source Gate Drain 1.E-05 Trap density small x y φ S0 Poly-Si φ SL Id(A) 1.E-07 1.E-09 large φ b0 Display Substrate (Insulator) φ bl 1.E-11 Traps 1.E Vg(V) HiSIM 29

30 Modeling of Trap Density Grain Boundaries Poly-Si film Traps uniformly distributed in crystal Si Simplified Model for Density of States Log(Density of States) Tail States Donor-type Acceptor-type Log(Density of States) Donor-type EV E g D E = gc1 exp Es ( ) Acceptor-type E EC ( E) = g exp g A C1 Es E V Deep States E C E V E C Add into the Poisson equation HiSIM 30

31 I-V characteristics 6.0 measurements simulations L=2μm 1.E+00 Ids(a.u.) L=2μm Ids(a.u.) 1.E-02 1.E-04 1.E-06 1.E-08 measurements simulations Vds(V) E Vgs(V) Ids(a.u.) measurements simulations L=0.5μm Ids(a.u.) L=0.5μm 1.E+00 1.E-02 1.E-04 1.E-06 1.E-08 measurements simulations Vds(V) E Vgs(V) S. Miyano et al., Proc. SISPAD, HiSIM 31

32 HiSIM-HV a few hundred volts > Bias Range > a few volts modeling MOSFET + Resistor HiSIM 32

33 Potential Drop in Drift symbol: HiSIM HV line: 2D Device N drift =10 17 cm 3 : low resistive N drift =10 16 cm 3 : high resistive : without resistance HiSIM 33

34 Specific Feature of HV MOSFET Rd = f(v gs, V ddp, model parameters) HiSIM 34

35 Current-Voltage Characteristics Relatively Low Breakdown Voltage Relatively High Breakdown Voltage Y. Oritsuki et al., IEEE TED, Oct. 2010; A. Tanaka et al, July, HiSIM 35

36 HiSIM-IGBT: Bias Range > 500V Schematic structure of a modern trench-igbt Jn n - (base) Simplified circuit diagram of the HiSIM-IGBT model Consistent potential extension in HiSIM-IGBT is achieved by calculation based on Kirchhoff s law. HiSIM 36

37 N base Dependence of I-V Characteristics M. Miyake et al., IEEE PESC, pp , June HiSIM 37

38 Summary HiSIM is a compact surface-potential-based MOSFET with a minimum number of approximations, due to its iterative surface-potential determination. HiSIM allows to preserve a consistent potential-based modeling in its extension to other integrated-device structures containing a MOSFET core. A compact-model family covering all integrated devices containing a MOSFET core and sharing the same modeling concepts could be developed. HiSIM 38