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The separated shorted-anode insulated gate bipolar transistor with the suppressed negative differential resistance regime
Microelectronics Journal Microelectronics Journal 30 (1999) 571–575
The separated shorted-anode insulated gate bipolar transistor with the suppressed negative differential resistance regime D.S. Byeon a, J.H. Chun a, B.H. Lee a, D.Y. Kim a, M.K. Han a, Y.I. Choi b a
School of Electrical Engineering, Seoul National University, Seoul 151-742, South Korea School of Electronics Engineering, Ajou University, Wonchun-dong, Suwon 442-749, South Korea
b
Accepted 23 November 1998
Abstract The separated shorted-anode LIGBT (SSA-LIGBT), which suppresses effectively the negative differential resistance regime, is investigated by performing 2-dimensional numerical simulation. In order to suppress the negative differential resistance regime, the SSA-LIGBT increases the pinch resistance by employing the highly resistive n-drift region as an electron conduction path instead of the lowly resistive n buffer region of the conventional SA-LIGBT. The SSA-LIGBT shows the remarkably decreased forward voltage drop when compared with the conventional SA-LIGBT and shows the one-order faster turn-off time than that of the LIGBT. 䉷 1999 Elsevier Science Ltd. All rights reserved. Keywords: Shorted-anode; Lateral insulated gate bipolar transistor; Negative differential resistance
1. Introduction The lateral insulated gate bipolar transistor (LIGBT) [1] is a suitable power device for high voltage power integrated circuit (PIC) owing to their low forward voltage drop [2]. The low forward voltage drop of LIGBT depends on the conductivity modulation of the high resistive n-drift region by injection of minority carrier. However, the LIGBT exhibits a large turn-off time because the stored charge in the n-drift region is only eliminated by the recombination rate. The shorted-anode lateral insulated gate bipolar transistor (SA-LIGBT) has the fast switching speed as compared with the LIGBT by using the shorted n ⫹ anode. The shorted n ⫹ anode provides an electron conduction path during turn-off so that the electron in the drift region can be extracted rapidly [3]. However, the SA-LIGBT inherently exhibits the negative differential resistance regime which results from the two different conduction mechanism, i.e., the MOS mode and the transistor mode [4]. The device should be operated in high current density level in order to avoid the negative differential resistance regime. However, the high current level operation may lead to a parasitic latchup phenomenon and an increase of the forward voltage drop [5]. In this article, we present the device characteristics of the separated shorted-anode LIGBT (SSA-LIGBT) in order to suppress negative differential resistance regime owing to an increased pinch resistance. The SSA-LIGBT employs the
high resistive n-drift region as an electron conduction path instead of the highly doped n buffer of the conventional SALIGBT. Although the effect of the separation of the p ⫹ anode and the shorted n ⫹ anode on the SA-LIGBT without n buffer has been reported briefly [6], there is no investigation of the device characteristics of the SA-LIGBT with n buffer. The device characteristics of the SSA-LIGBT are verified and investigated by performing 2-dimensional numerical simulation with MEDICI. [7]
2. Device structure and operation Fig. 1 shows the cross-sectional view and the equivalent circuit of the conventional SA-LIGBT. In order to turn-on the device, when the positive gate voltage and low anode voltage are applied, the electron carriers flow from the n ⫹ source via the n-channel and are collected by the shorted n ⫹ anode. The device operates like the MOS. As the anode voltage increases, the flow of electron carriers produces the voltage drop (VRB) across the pinch resistor RB in the n buffer underneath the p ⫹ anode region. If the voltage drop VRB increases up to the built-in potential (Vbi) at the p ⫹ anode/n buffer junction, the hole carriers are injected from the p ⫹ anode into the n-drift region, resulting in the conductivity modulation of the n-drift region. That is, the device operates like the transistor. The negative differential
0026-2692/99/$ - see front matter 䉷 1999 Elsevier Science Ltd. All rights reserved. PII: S0026-269 2(98)00180-3
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D.S. Byeon et al. / Microelectronics Journal 30 (1999) 571–575 Table 1 The device parameters used for simulation n ⫹ shorted anode p ⫹ anode n buffer Length p ⫹ anode n ⫹ shorted anode n-Drift region Doping concentration Length Thickness Distance between the p ⫹ anode and the separated n ⫹ shorted anode, LS Surface doping concentration
10 20 cm ⫺3 10 19 cm ⫺3 5 × 10 16 cm ⫺3 5 mm 2.5 mm 2 × 10 15 m ⫺3 20 mm 5 mm 1 mm
and the shorted n ⫹ anode because the doping concentration of the n-drift region is lower by more than one order when compared with that of the n buffer. The separated shorted anode is fabricated with the same process for n ⫹ source.
3. Simulation results and discussion 3.1. Forward I–V characteristics
Fig. 1. The conventional SA-LIGBT (a) the cross-sectional view and (b) the equivalent circuit.
resistance regime is occurred by the change of conduction mode from the MOS to the transistor. In order to suppress the negative differential resistance regime, it is desirable to decrease the latching current by increasing the pinch resistance RB in the n buffer underneath the p ⫹ anode region as shown in Fig. 1 [2]. However, the pinch resistance of the conventional SALIGBT is not effectively increased because the pinch resistance depends strongly on the highly doped n buffer region where the very high doping concentration should be chosen within 5 × 10 16 cm ⫺3 to 2 × 10 17 cm ⫺3 in order to prevent the punch through phenomenon. The SSA-LIGBT employs the separated shorted-anode structure as shown in Fig. 2. The pinch resistance of the SSA-LIGBT increases significantly owing to the resistance RD in the high resistive n-drift region between the p ⫹ anode
Fig. 2. The cross-sectional view of the separated shorted-anode LIGBT (SSA-LIGBT).
The device parameters used for the simulation are listed in Table 1. The simulated I–V characteristics of the various devices such as SSA-LIGBT, SA-LIGBT, LIGBT, MOS are shown in Fig. 3. The forward blocking voltage was 150 V. As shown in the figure, the negative differential resistance regime is considerably suppressed for the SSA-LIGBT as compared with the conventional SA-LIGBT. The latching current of the SSA-LIGBT is 70 A/cm 2, while that of the conventional SA-LIGBT is 140 A/cm 2. It is noticeable that the negative differential resistance regime of the SA-LIGBT influences the wide device operation range where the anode current reaches up to 260 A/cm 2. At anode current density of 200 A/cm 2, the forward voltage drop of the SSA-LIGBT is 1.5 V which is much lower than that of MOS by 7.3 V and higher than that of the LIGBT by 0.3 V. The effectiveness of the SSA-LIGBT is enhanced when the high doping concentration in the n buffer is required for the complete prevention of the punch through phenomenon.
Fig. 3. The I–V characteristics of the SSA-LIGBT when compared with the conventional SA-LIGBT, LIGBT and LDMOS.
D.S. Byeon et al. / Microelectronics Journal 30 (1999) 571–575
Fig. 4. The 2-dimensional current flow lines at anode current density of 150 A/cm 2 (a) the SSA-LIGBT with LS 1 mm and (b) the conventional SA-LIGBT.
Fig. 4 shows the 2-dimensional current flow lines at anode current density of 150 A/cm 2. It is shown that the SSA-LIGBT operates in transistor mode with hole injection from p ⫹ anode region into the n-drift region. The conventional SA-LIGBT operates in MOS mode. That is, only the electron current flows from the n ⫹ source to the shorted n ⫹ anode through the n-channel and the n buffer. The minority carrier (hole) is not injected from p ⫹ anode. Fig. 5 shows the I–V characteristics with varying design
573
parameters of anode. As the distance between the p ⫹ anode and the separated n ⫹ shorted anode (LS) increases from 1 to 5 mm, the SSA-LIGBT shows the decreased negative differential resistance regime owing to the increased resistance RD as shown in Fig. 2. In order to suppress the negative differential resistance regime in the conventional SA-LIGBT, a long p ⫹ anode should be used, resulting in the considerable increase of consumed device area. For example, in order to obtain the negative differential resistance regime which is comparable to that of the SSA-LIGBT with LS of 1 mm, the p ⫹ anode length should be increased up to 11 mm which is about one forth of the total device length. In the SSA-LIGBT, the design parameters of the n-drift region such as the doping concentration, thickness and length have stronger effects on the suppression of the negative differential resistance regime because of the RD component in the n-drift region. We have investigated the latching current with the various design parameters of the n-drift region. As shown in Fig. 6, the latching current of the SSA-LIGBT shows a lower value than that of the conventional SA-LIGBT irrespective of the doping concentration (Ndrift) of the n-drift region. The SSA-LIGBT shows the transistor operation over the whole Ndrift range because the RD component increases with the decreased Ndrift. The simulated I–V characteristics showed that the SSA-LIGBT suppresses remarkably the negative differential resistance regime for Ndrift less than 10 15 cm ⫺3 owing to the RD component in the n-drift region. The conventional SA-LIGBT operates like the MOS for the low Ndrift less than 4 × 10 14 cm ⫺3. In the conventional SA-LIGBT, when the Ndrift decreases, the resistance in the n-drift region between the p ⫹ anode and the p ⫹ cathode increases. Therefore, the majority of the anode voltage is applied across the n-drift region between the p ⫹ anode and the p ⫹ cathode so that the VRB is not effectively increased up to built-in potential. Fig. 7 shows the negative differential resistance regime of the SSA-LIGBT in terms of the thickness (Tdrift) and the length (Ldrift) of the n-drift region. As shown in Fig. 7(a), the negative differential resistance regime is increased with the increased Ldrift. It can be explained by the fact that, during the MOS operation, the voltage drop across the ndrift region between the p-base and the p ⫹ anode increases, resulting in the increased anode voltage corresponding to the latching current [8]. In Fig. 7(b), the latching current decreases with decreasing Tdrift because the resistance RD increases geometrically. 3.2. Turn-off characteristics
Fig. 5. The I–V characteristics of the SSA-LIGBT and the conventional SA-LIGBT with varing the LS.
The turn-off characteristics of the SSA-LIGBT were investigated through resistive load simulation. The turn-off simulation was performed at an anode current of 200 A/cm 2 by ramping the gate voltage from 15 to 0 V in 50 ns. The waveforms of the SSA-LIGBT, the conventional SALIGBT and LIGBT are shown in Fig. 8. The SSA-LIGBT and the conventional SA-LIGBT show more than one order
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D.S. Byeon et al. / Microelectronics Journal 30 (1999) 571–575
Fig. 8. The turn-off waveforms of the SSA-LIGBT, the conventional SALIGBT and the LIGBT. Fig. 6. The I–V characteristics of the SSA-LIGBT and the conventional SA-LIGBT.
faster turn-off speed than that of the LIGBT because of the fast extraction of electron by the shorted anode structure. Fig. 9 shows the turn-off waveforms of the SSA-LIGBT with varying the LS when compared with those of the various devices. The turn-off time increases slightly as the LS increases from 1 to 5 mm because of the increased minor-
ity carrier injection from the p ⫹ anode. In the conventional SA-LIGBT, there is no tail current because the minority carrier was not injected in the n-drift region. It shows that the negative differential resistance regime influences over the anode current of 200 A/cm 2.
4. Conclusion The device characteristics of the separated shorted-anode LIGBT have been investigated by 2-dimensional numerical simulation. It was shown that the negative differential resistance regime was significantly reduced without additional process step and mask. The forward voltage drop of the SSA-LIGBT is decreased when compared with that of the conventional SA-LIGBT because of the initiation of hole injection from p ⫹ anode into the n-drift region at low anode current. The SSA-LIGBT shows a remarkable suppression of the negative differential regime for the doping concentration less than 10 15 cm ⫺3 of the n-drift region. The switching speed of the SSA-LIGBT is about one order lower than that of the LIGBT. The SSA-LIGBT may be an attractive device to the power integrated circuit (PIC).
Fig. 7. The I–V characteristics of the SSA-LIGBT and the conventional SA-LIGBT in terms of the length (Ldrift) and (b) the thickness (Tdrift) of the ndrift region.
Fig. 9. The turn-off waveforms of the various devices and the SSA-LIGBT with varying LS.
D.S. Byeon et al. / Microelectronics Journal 30 (1999) 571–575
Acknowledgement This work was supported by the G7 project through the Korean Ministry of Science and Technology.
[4]
[5]
References [6] [1] R. Jayaraman, V. Rumennik, B. Singer, E.H. Stupp, Comparison of high voltage devices for power integrated circuits, IEDM Tech. Dig. (1984) 258–261. [2] J.K.O. Sin, S. Mukherjee, Lateral insulated-gate bipolar transistor (LIGBT) with a segmented anode structure, IEEE Electron Device Letters (1991) 45–47. [3] P.A. Gough, M.R. Simpson, V. Rumenik, Fast switching lateral
[7]
[8]
575
insulated gate transistor, IEDM Tech. Dig. Los Angeles (1986) 218– 221. M.R. Simpson, Analysis of negative differential resistance in the I–V characteristics of shorted-anode LIGBT’s, IEEE Trans. on Electron Devices (1991) 1633–1640. B.H. Lee, W.O. Lee, M.S. Lim, J.E. Park, M.K. Han, Y.I. Choi, A new dual-gate SOI LIGBT with the shorted anode, Proc. SSDM’96, Yokohama, 1996, pp. 287–289 TMA MEDICI, two dimensional device simulation program, user’s manual, 1996 S. Mukherjee, M. Amato, V. Rumennik, Influence of device structure on the transient and steady state characteristics of LIGT, Proc. ISPSD’96, Maui, 1996, pp. 310–317 B.H. Lee, D.S. Byeon, D.Y. Kim, W.O. Lee, M.K. Han, Y.I. Choi, Dual gate shorted anode SOI lateral insulated gate bipolar transistor suppressing the snap-back, Japanese Journal of Applied Physics (1997) 1663–1666.
The separated shorted-anode insulated gate bipolar transistor with the suppressed negative differential resistance regime D.S. Byeon a, J.H. Chun a, B.H. Lee a, D.Y. Kim a, M.K. Han a, Y.I. Choi b a
School of Electrical Engineering, Seoul National University, Seoul 151-742, South Korea School of Electronics Engineering, Ajou University, Wonchun-dong, Suwon 442-749, South Korea
b
Accepted 23 November 1998
Abstract The separated shorted-anode LIGBT (SSA-LIGBT), which suppresses effectively the negative differential resistance regime, is investigated by performing 2-dimensional numerical simulation. In order to suppress the negative differential resistance regime, the SSA-LIGBT increases the pinch resistance by employing the highly resistive n-drift region as an electron conduction path instead of the lowly resistive n buffer region of the conventional SA-LIGBT. The SSA-LIGBT shows the remarkably decreased forward voltage drop when compared with the conventional SA-LIGBT and shows the one-order faster turn-off time than that of the LIGBT. 䉷 1999 Elsevier Science Ltd. All rights reserved. Keywords: Shorted-anode; Lateral insulated gate bipolar transistor; Negative differential resistance
1. Introduction The lateral insulated gate bipolar transistor (LIGBT) [1] is a suitable power device for high voltage power integrated circuit (PIC) owing to their low forward voltage drop [2]. The low forward voltage drop of LIGBT depends on the conductivity modulation of the high resistive n-drift region by injection of minority carrier. However, the LIGBT exhibits a large turn-off time because the stored charge in the n-drift region is only eliminated by the recombination rate. The shorted-anode lateral insulated gate bipolar transistor (SA-LIGBT) has the fast switching speed as compared with the LIGBT by using the shorted n ⫹ anode. The shorted n ⫹ anode provides an electron conduction path during turn-off so that the electron in the drift region can be extracted rapidly [3]. However, the SA-LIGBT inherently exhibits the negative differential resistance regime which results from the two different conduction mechanism, i.e., the MOS mode and the transistor mode [4]. The device should be operated in high current density level in order to avoid the negative differential resistance regime. However, the high current level operation may lead to a parasitic latchup phenomenon and an increase of the forward voltage drop [5]. In this article, we present the device characteristics of the separated shorted-anode LIGBT (SSA-LIGBT) in order to suppress negative differential resistance regime owing to an increased pinch resistance. The SSA-LIGBT employs the
high resistive n-drift region as an electron conduction path instead of the highly doped n buffer of the conventional SALIGBT. Although the effect of the separation of the p ⫹ anode and the shorted n ⫹ anode on the SA-LIGBT without n buffer has been reported briefly [6], there is no investigation of the device characteristics of the SA-LIGBT with n buffer. The device characteristics of the SSA-LIGBT are verified and investigated by performing 2-dimensional numerical simulation with MEDICI. [7]
2. Device structure and operation Fig. 1 shows the cross-sectional view and the equivalent circuit of the conventional SA-LIGBT. In order to turn-on the device, when the positive gate voltage and low anode voltage are applied, the electron carriers flow from the n ⫹ source via the n-channel and are collected by the shorted n ⫹ anode. The device operates like the MOS. As the anode voltage increases, the flow of electron carriers produces the voltage drop (VRB) across the pinch resistor RB in the n buffer underneath the p ⫹ anode region. If the voltage drop VRB increases up to the built-in potential (Vbi) at the p ⫹ anode/n buffer junction, the hole carriers are injected from the p ⫹ anode into the n-drift region, resulting in the conductivity modulation of the n-drift region. That is, the device operates like the transistor. The negative differential
0026-2692/99/$ - see front matter 䉷 1999 Elsevier Science Ltd. All rights reserved. PII: S0026-269 2(98)00180-3
572
D.S. Byeon et al. / Microelectronics Journal 30 (1999) 571–575 Table 1 The device parameters used for simulation n ⫹ shorted anode p ⫹ anode n buffer Length p ⫹ anode n ⫹ shorted anode n-Drift region Doping concentration Length Thickness Distance between the p ⫹ anode and the separated n ⫹ shorted anode, LS Surface doping concentration
10 20 cm ⫺3 10 19 cm ⫺3 5 × 10 16 cm ⫺3 5 mm 2.5 mm 2 × 10 15 m ⫺3 20 mm 5 mm 1 mm
and the shorted n ⫹ anode because the doping concentration of the n-drift region is lower by more than one order when compared with that of the n buffer. The separated shorted anode is fabricated with the same process for n ⫹ source.
3. Simulation results and discussion 3.1. Forward I–V characteristics
Fig. 1. The conventional SA-LIGBT (a) the cross-sectional view and (b) the equivalent circuit.
resistance regime is occurred by the change of conduction mode from the MOS to the transistor. In order to suppress the negative differential resistance regime, it is desirable to decrease the latching current by increasing the pinch resistance RB in the n buffer underneath the p ⫹ anode region as shown in Fig. 1 [2]. However, the pinch resistance of the conventional SALIGBT is not effectively increased because the pinch resistance depends strongly on the highly doped n buffer region where the very high doping concentration should be chosen within 5 × 10 16 cm ⫺3 to 2 × 10 17 cm ⫺3 in order to prevent the punch through phenomenon. The SSA-LIGBT employs the separated shorted-anode structure as shown in Fig. 2. The pinch resistance of the SSA-LIGBT increases significantly owing to the resistance RD in the high resistive n-drift region between the p ⫹ anode
Fig. 2. The cross-sectional view of the separated shorted-anode LIGBT (SSA-LIGBT).
The device parameters used for the simulation are listed in Table 1. The simulated I–V characteristics of the various devices such as SSA-LIGBT, SA-LIGBT, LIGBT, MOS are shown in Fig. 3. The forward blocking voltage was 150 V. As shown in the figure, the negative differential resistance regime is considerably suppressed for the SSA-LIGBT as compared with the conventional SA-LIGBT. The latching current of the SSA-LIGBT is 70 A/cm 2, while that of the conventional SA-LIGBT is 140 A/cm 2. It is noticeable that the negative differential resistance regime of the SA-LIGBT influences the wide device operation range where the anode current reaches up to 260 A/cm 2. At anode current density of 200 A/cm 2, the forward voltage drop of the SSA-LIGBT is 1.5 V which is much lower than that of MOS by 7.3 V and higher than that of the LIGBT by 0.3 V. The effectiveness of the SSA-LIGBT is enhanced when the high doping concentration in the n buffer is required for the complete prevention of the punch through phenomenon.
Fig. 3. The I–V characteristics of the SSA-LIGBT when compared with the conventional SA-LIGBT, LIGBT and LDMOS.
D.S. Byeon et al. / Microelectronics Journal 30 (1999) 571–575
Fig. 4. The 2-dimensional current flow lines at anode current density of 150 A/cm 2 (a) the SSA-LIGBT with LS 1 mm and (b) the conventional SA-LIGBT.
Fig. 4 shows the 2-dimensional current flow lines at anode current density of 150 A/cm 2. It is shown that the SSA-LIGBT operates in transistor mode with hole injection from p ⫹ anode region into the n-drift region. The conventional SA-LIGBT operates in MOS mode. That is, only the electron current flows from the n ⫹ source to the shorted n ⫹ anode through the n-channel and the n buffer. The minority carrier (hole) is not injected from p ⫹ anode. Fig. 5 shows the I–V characteristics with varying design
573
parameters of anode. As the distance between the p ⫹ anode and the separated n ⫹ shorted anode (LS) increases from 1 to 5 mm, the SSA-LIGBT shows the decreased negative differential resistance regime owing to the increased resistance RD as shown in Fig. 2. In order to suppress the negative differential resistance regime in the conventional SA-LIGBT, a long p ⫹ anode should be used, resulting in the considerable increase of consumed device area. For example, in order to obtain the negative differential resistance regime which is comparable to that of the SSA-LIGBT with LS of 1 mm, the p ⫹ anode length should be increased up to 11 mm which is about one forth of the total device length. In the SSA-LIGBT, the design parameters of the n-drift region such as the doping concentration, thickness and length have stronger effects on the suppression of the negative differential resistance regime because of the RD component in the n-drift region. We have investigated the latching current with the various design parameters of the n-drift region. As shown in Fig. 6, the latching current of the SSA-LIGBT shows a lower value than that of the conventional SA-LIGBT irrespective of the doping concentration (Ndrift) of the n-drift region. The SSA-LIGBT shows the transistor operation over the whole Ndrift range because the RD component increases with the decreased Ndrift. The simulated I–V characteristics showed that the SSA-LIGBT suppresses remarkably the negative differential resistance regime for Ndrift less than 10 15 cm ⫺3 owing to the RD component in the n-drift region. The conventional SA-LIGBT operates like the MOS for the low Ndrift less than 4 × 10 14 cm ⫺3. In the conventional SA-LIGBT, when the Ndrift decreases, the resistance in the n-drift region between the p ⫹ anode and the p ⫹ cathode increases. Therefore, the majority of the anode voltage is applied across the n-drift region between the p ⫹ anode and the p ⫹ cathode so that the VRB is not effectively increased up to built-in potential. Fig. 7 shows the negative differential resistance regime of the SSA-LIGBT in terms of the thickness (Tdrift) and the length (Ldrift) of the n-drift region. As shown in Fig. 7(a), the negative differential resistance regime is increased with the increased Ldrift. It can be explained by the fact that, during the MOS operation, the voltage drop across the ndrift region between the p-base and the p ⫹ anode increases, resulting in the increased anode voltage corresponding to the latching current [8]. In Fig. 7(b), the latching current decreases with decreasing Tdrift because the resistance RD increases geometrically. 3.2. Turn-off characteristics
Fig. 5. The I–V characteristics of the SSA-LIGBT and the conventional SA-LIGBT with varing the LS.
The turn-off characteristics of the SSA-LIGBT were investigated through resistive load simulation. The turn-off simulation was performed at an anode current of 200 A/cm 2 by ramping the gate voltage from 15 to 0 V in 50 ns. The waveforms of the SSA-LIGBT, the conventional SALIGBT and LIGBT are shown in Fig. 8. The SSA-LIGBT and the conventional SA-LIGBT show more than one order
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D.S. Byeon et al. / Microelectronics Journal 30 (1999) 571–575
Fig. 8. The turn-off waveforms of the SSA-LIGBT, the conventional SALIGBT and the LIGBT. Fig. 6. The I–V characteristics of the SSA-LIGBT and the conventional SA-LIGBT.
faster turn-off speed than that of the LIGBT because of the fast extraction of electron by the shorted anode structure. Fig. 9 shows the turn-off waveforms of the SSA-LIGBT with varying the LS when compared with those of the various devices. The turn-off time increases slightly as the LS increases from 1 to 5 mm because of the increased minor-
ity carrier injection from the p ⫹ anode. In the conventional SA-LIGBT, there is no tail current because the minority carrier was not injected in the n-drift region. It shows that the negative differential resistance regime influences over the anode current of 200 A/cm 2.
4. Conclusion The device characteristics of the separated shorted-anode LIGBT have been investigated by 2-dimensional numerical simulation. It was shown that the negative differential resistance regime was significantly reduced without additional process step and mask. The forward voltage drop of the SSA-LIGBT is decreased when compared with that of the conventional SA-LIGBT because of the initiation of hole injection from p ⫹ anode into the n-drift region at low anode current. The SSA-LIGBT shows a remarkable suppression of the negative differential regime for the doping concentration less than 10 15 cm ⫺3 of the n-drift region. The switching speed of the SSA-LIGBT is about one order lower than that of the LIGBT. The SSA-LIGBT may be an attractive device to the power integrated circuit (PIC).
Fig. 7. The I–V characteristics of the SSA-LIGBT and the conventional SA-LIGBT in terms of the length (Ldrift) and (b) the thickness (Tdrift) of the ndrift region.
Fig. 9. The turn-off waveforms of the various devices and the SSA-LIGBT with varying LS.
D.S. Byeon et al. / Microelectronics Journal 30 (1999) 571–575
Acknowledgement This work was supported by the G7 project through the Korean Ministry of Science and Technology.
[4]
[5]
References [6] [1] R. Jayaraman, V. Rumennik, B. Singer, E.H. Stupp, Comparison of high voltage devices for power integrated circuits, IEDM Tech. Dig. (1984) 258–261. [2] J.K.O. Sin, S. Mukherjee, Lateral insulated-gate bipolar transistor (LIGBT) with a segmented anode structure, IEEE Electron Device Letters (1991) 45–47. [3] P.A. Gough, M.R. Simpson, V. Rumenik, Fast switching lateral
[7]
[8]
575
insulated gate transistor, IEDM Tech. Dig. Los Angeles (1986) 218– 221. M.R. Simpson, Analysis of negative differential resistance in the I–V characteristics of shorted-anode LIGBT’s, IEEE Trans. on Electron Devices (1991) 1633–1640. B.H. Lee, W.O. Lee, M.S. Lim, J.E. Park, M.K. Han, Y.I. Choi, A new dual-gate SOI LIGBT with the shorted anode, Proc. SSDM’96, Yokohama, 1996, pp. 287–289 TMA MEDICI, two dimensional device simulation program, user’s manual, 1996 S. Mukherjee, M. Amato, V. Rumennik, Influence of device structure on the transient and steady state characteristics of LIGT, Proc. ISPSD’96, Maui, 1996, pp. 310–317 B.H. Lee, D.S. Byeon, D.Y. Kim, W.O. Lee, M.K. Han, Y.I. Choi, Dual gate shorted anode SOI lateral insulated gate bipolar transistor suppressing the snap-back, Japanese Journal of Applied Physics (1997) 1663–1666.