Electric Field Modulation Effect Research Articles

Analytical Model for the Surrounded Field Plate in Folded Lateral MOSFET Structure

A novel unified analytical model concerning the surrounded plate field is proposed for extended drain MOSFETs (EDMOS) in this article for the first time. The SFP analytical model demonstrates the edge-assisted depletion (AD) effect and the multidimensional AD effect through the dielectric-layer (DL) potential function and 3-D Poisson equation. The closed-form solutions of the electric field and potential distributions are derived to predict the breakdown voltage (BV) for different SFP lengths and dielectric parameters. The 3-D electric field modulation effect brought on by SFP is presented. The impact of SFP parameters on BV is explained using the effective doping concentration ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{N}_{\text{deff}}\text{)}$</tex-math> </inline-formula> . The analytical model takes into account the multidimensional conduction path and the electron accumulation effect while determining the specific ON-resistance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{R}_{\text{on},\textit{sp}}\text{)}$</tex-math> </inline-formula> of SFP EDMOS. The proposed model is useful for the trade-off between mobility and doping concentration. It can also analyze the impact of the strain on BV and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{R}_{\text{on},\textit{sp}}$</tex-math> </inline-formula> . The analytical model is validated by the good agreement between the modeling results and simulation results.

Electric field modulation effect and mechanism on n-alkanes fuel pyrolysis: A ReaxFF MD and DFT study

To promote the fuel utilization efficiency in the aviation and space transport, the electric field was selected as an efficiency method to modify the fuel pyrolysis rate. This work investigated the surrogate fuel component n-alkane (n-pentane, n-heptane and n-decane) pyrolysis process under the electric field. The three n-alkanes pyrolysis rate and reaction pathway were analyzed. And the reaction mechanism under the electric field was discussed by the bond cracking potential energy (PES), system thermal motion and energy. The molecular dynamics results showed the n-alkanes pyrolysis was modulated by the electric field strength, which promotion in weak electric field and inhibition in strong field. The species transformation net was complicated and selective while the conversion flux was reduced by the strong field. The field improved the molecule polarization and deformation to result in the edged carbon bond and H bond dissociation with lower energy barriers. Analyzing the molecular motion and system energy, the intermolecular distance was elongated, and interaction energy was reduced, which caused to the decrease of collision frequency under the field. The contribution of electric field to the single molecule decomposition and inhibition molecules motion worked together on the global n-alkane pyrolysis. This work supplied a theory support to the promoting fuel utilization using the electric energy.

Exact Relationship between Black Phosphorus Thickness and Behaviors of Field-Effect Transistors

As a two-dimensional (2D) semiconductor material with excellent optoelectronic properties, black phosphorus (BP) has attracted widespread attention. It was found that the energy band structure of BP crystal changes with its thickness if BP is thin. To explore the accurate effects of the BP thicknesses on devices, BP-FETs with different BP thickness (50 nm, 40 nm, 30 nm, 20 nm, and 6 nm) as the channel material were fabricated by mechanical exfoliation technique. The output characteristics and transfer characteristics of the BP-FETs were analyzed in detail. The source–drain current (Ids) of devices is directly related to the BP thickness. The larger the BP thickness, the larger the Ids obtained under the same gate voltage modulation, but the electric field modulation effect decreases. Especially, the correlation between Ids and BP thickness can be described by a semi-empirical formula, which predicts that only when the BP thickness is less than 21.7 nm, the band structure of BP will be significantly affected by the thickness. The mobility of the carrier increases with the increasing of the BP thickness; for BP thickness of 6 nm, 20 nm, 30 nm, 40 nm, and 50 nm, the mobility is about 52.5 cm2/Vs, 187.5 cm2/Vs, 214.4 cm2/Vs, 252.5 cm2/Vs, and 336.4 cm2/Vs. Finally, the 50 nm BP in FET was etched to 30 nm using plasma etching technology to further verify the above experimental results. It also confirmed that plasma etching methods tend to introduce structural damage and impurity elements, which in turn has an impact on the output characteristics of the device.

Effect of Electric Field Modulation on The Onset of Electroconvection in a Couple Stress Fluid

The problem of a convectional instability in a horizontal dielectric fluid layer with electric field modulation under couple stress fluid is examined. The horizontal dielectric upper boundary fluid layer is cooled, and the lower boundary is subjected to an isothermal boundary condition. The regular perturbation method based on the small magnitude of modulation is used to compute the critical Rayleigh number and the corresponding wavenumber. The solidity of the system is the characterised by a correction Rayleigh number, which is computed as a function of thermal, electric, and couple stress parameters and the frequency of electric field modulation. Some of the known findings are retrieved as specific cases in this study. It is demonstrated that the onset of the convection may be advanced or delayed by the proper regulation of different regulation parameters. The outcomes of this study have potential implications for the control of electroconvection with a time-dependent electric field.

Mechanism of Linearity Improvement in GaN HEMTs by Low Pressure Chemical Vapor Deposition-SiN x Passivation

The mechanism of linearity improvement in AlGaN/GaN high-electron mobility transistors (HEMTs) by low pressure chemical vapor deposition (LPCVD)-SiNx passivation is verified using an asymmetric passivation structure, based on different two-dimensional electron gas (2DEG) enhancement capability between LPCVD-SiNx and SiO2 passivation grown by plasma-enhanced CVD (PECVD). The fabricated AlGaN/GaN HEMTs with a hybrid LPCVD-SiNx/PECVD-SiO2 passivation structure deliver a linearity figure of merit third-order intermodulation point (OIP3)/PDC of 4.36 dB, which is 2.84 dB higher than HEMTs with pure PECVD-SiO2 passivation. Benefiting from the charge and electric field modulation effect of the LPCVD-SINx in the source-gate access region of HEMTs, the current-dependent nonlinear source access resistance is remarkably improved, especially at high current level over 500 mA/mm and high temperature. LPCVD-SINx could be a compelling passivation for the fabrication of high linearity GaN-based power HEMTs.

Numerical Analysis for a P-Drift Region N-IGBT With Enhanced Dynamic Electric Field Modulation Effect

This article studies the underlying physical mechanism and comprehensive characteristics of the N-channel IGBT (N-IGBT) with P-drift region (PD-IGBT). Distinguishing from the conventional N-IGBT with N-drift region (ND-IGBT), the main blocking junction ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${J}_{\text {MB}}$ </tex-math></inline-formula> ) of the PD-IGBT is changed from the emitter side to the collector side, which leads to a significant enhancement effect of dynamic electric field modulation. Based on the effect, the PD-IGBT features fast dynamic electric field (E-field) building speed in the drift region and a high E-field at the edge of the field-stop (FS) layer, which can extract excess carriers stored in the device rapidly during the turn-off transient, thus reducing the turn-off loss ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}_{\rm {OFF}}$ </tex-math></inline-formula> ) and turn-off time ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t}_{\rm {OFF}}$ </tex-math></inline-formula> ) of the device. Moreover, the change of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${J}_{\text {MB}}$ </tex-math></inline-formula> location can also alleviate the E-field crowding phenomenon at the trench gate corner, thus providing an optimized relationship between breakdown voltage (BV) and ON-state voltage, as well as high avalanche energy. Simulation results show that, when compared with the state-of-the-art N-channel ND-IGBT, the PD-IGBT offers 46% shorter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t}_{\rm {OFF}}$ </tex-math></inline-formula> , 57% lower <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}_{\rm {OFF}}$ </tex-math></inline-formula> , and 60% larger avalanche energy without compromising other device characteristics.

The Drift Region Width Modulation Technique for Breakdown Performance Enhancement of AlGaN/GaN HEMT

The breakdown performance of the AlGaN/GaN high electron mobility transistor (HEMT) is limited by the high electric field peaks in the device. To obtain a more uniform electric field distribution, the drift region width modulation (DWM) technique is proposed to reshape the charge distribution between the gate and drain electrodes. By applying the Gaussian box method, an effective designing guidance for the structure optimization of the AlGaN/GaN HEMT with adaptive-width drift region pillars (AWD-HEMT) is obtained. The fabricated AWD-HEMT demonstrated a significant improvement in breakdown performance. The Baliga’s figure of merit (BFOM) of AWD-HEMT improved 65.3% compared with the conventional HEMT, without introducing complicated processes. In addition, the mechanism of the AWD-HEMT is explored by numerical methods. The simulations indicate that a more uniform electric field distribution at AlGaN/GaN interfaces could be obtained, and the increased varying rate of the adaptive-width drift region (AWD) pillars results in a more obvious electric field modulation effect.

Novel Vertical Power MOSFET With Step Hk Insulator Close to Super Junction Limit Relationship Between Breakdown Voltage and Specific ON-Resistance by Improving Electric Field Modulation

A new vertical double-diffused metal oxide semiconductor field effect transistor (MOSFET) is presented based on the high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> (Hk) MOSFET concept in this article with the step high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${k}$ </tex-math></inline-formula> insulator, named as step Hk vertical double-diffused metal oxide semiconductor (VDMOS), to improve the electric field modulation effect. For step Hk VDMOS, the depletion is increased by the electric field modulation effect of step Hk insulator, which decreases the specific on-resistance of step Hk VDMOS compared to the conventional Hk VDMOS. The various thickness of the Hk insulator modulates the vertical electric field distribution in the drift region, which increases the breakdown voltage (BV) of the step Hk VDMOS. Meanwhile, an analytical model for novel step Hk VDMOS is obtained by solving the 2-D Poisson equation in an N-type drift region, and the 2-D Laplace equation in the step Hk region, which can reasonably explain the modulation effect of the step Hk region on the electric field distribution. The results show that the BV of the step Hk VDMOS is increased from 639 V of the conventional Hk VDMOS to 736 V with the same drift length of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$42~\mu \text{m}$ </tex-math></inline-formula> . The theoretical results of the electrical characteristics are in good agreement with the results from numerical simulations.

Experimental Results for AlGaN/GaN HEMTs Improving Breakdown Voltage and Output Current by Electric Field Modulation

A depletion-mode AlGaN/GaN high electron mobility transistors (HEMTs) have been proposed in this article with the partial GaN cap, which applies the electric field modulation effect to optimize the surface electric field and two-dimensional electron gas (2DEG) distribution. The 2DEG density under the partial GaN cap is reduced due to the polarization effect formed by the partial GaN cap and AlGaN layers. The surface electric field is reshaped by the electric field modulation effect due to the partial GaN cap, featuring an extra electric field peak far away from the gate edge, which, therefore, improves the breakdown voltage (BV). Moreover, the output current ( ${I}_{\text {DS}}$ ) is also improved slightly resulting from the increased mobility of 2DEG, which compensates for the decrease in the 2DEG density. The experimental BV is increased greatly from 378 V for the conventional AlGaN/GaN HEMTs to 656 V for the depletion-mode partial cap layer AlGaN/GaN HEMTs because of the optimized surface electric field by the electric field modulation effect. The maximum output current ( ${I}_{\text {max}}$ ) is increased from 538 to 558 mA/mm. It is concluded that the BV can be improved significantly and ${I}_{\text {DS}}$ increased slightly for AlGaN/GaN HEMTs by the electric field modulation technique using the partial GaN cap, which optimizes the BV and specific ON-resistance ( ${R}_{ \mathrm{\scriptscriptstyle ON}, \text {sp}}$ ) simultaneously.

Novel Si/SiC Heterojunction Lateral Double-Diffused Metal Oxide Semiconductor With SIPOS Field Plate by Simulation Study

A novel Si/SiC heterojunction Lateral Double-diffused Metal Oxide Semiconductor with the Semi-Insulating Polycrystalline Silicon field plate (SIPOS Si/SiC LDMOS) is proposed in this paper for the first time. The innovative terminal technology of Breakdown Point Transfer (BPT) had been applied on Si/SiC MOSFETs. This creative technology improved Breakdown Voltage (BV) of the proposed device, compared with the conventional Si LDMOS (Cov. LDMOS). In order to optimize the trade-off between BV and Specific On-Resistance (RON,SP), the SIPOS field plate is applied on Si/SiC LDMOS for the first time in this paper. At On-State, due to the internal electric field of SIPOS filed plate, the majority carriers accumulation layer is formed on the surface of the drift region for the proposed SIPOS Si/SiC LDMOS, which means RON,SP will be reduced. Meanwhile, the electric field modulation effect of SIPOS field plate can make the surface electric field distribute evenly, which leads to an increase of BV. In addition, due to the high-thermal conductivity of SiC substrate, the heat-dissipation efficiency of the proposed device is significantly improved. The simulation results show that the BV of SIPOS Si/SiC LDMOS is 428.4V, which increased by 78.4% in comparison with Cov. LDMOS (BV of 240.0V) with the same structure parameters. The R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON,SP</sub> of SIPOS Si/SiC LDMOS is decreased from 33.2mΩ · cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of Cov. LDMOS to 24.0mΩ · cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , decreased by 27.7%. Furthermore, the figure-of-merit (FOM = BV <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on,sp</sub> ) of SIPOS Si/SiC LDMOS reaches 7.6MW/cm2, which means SIPOS Si/SiC LDMOS has enough performance to break the Silicon limit.

Novel fast-switching LIGBT with P-buried layer and partial SOI* *Project supported by the National Basic Research Program of China (Grant No. 2015CB351906) and the Science Foundation for Distinguished Young Scholars of Shaanxi Province, China (Grant No. 2018JC-017).

A novel silicon-on-insulator lateral insulated gate bipolar transistor (SOI LIGBT) is proposed in this paper. The proposed device has a P-type buried layer and a partial-SOI layer, which is called the BPSOI-LIGBT. Due to the electric field modulation effect generated by the P-type buried layer and the partial-SOI layer, the proposed structure generates two new peaks in the surface electric field distribution, which can achieve a smaller device size with a higher breakdown voltage. The smaller size of the device is beneficial to the fast switching. The simulation shows that under the same size, the breakdown voltage of the BPSOI LIGBT is 26% higher than that of the conventional partial-SOI LIGBT (PSOI LIGBT), and 84% higher than the traditional SOI LIGBT. When the forward voltage drop is 2.05 V, the turn-off time of the BPSOI LIGBT is 71% shorter than that of the traditional SOI LIGBT. Therefore, the proposed BPSOI LIGBT has a better forward voltage drop and turn-off time trade-off than the traditional SOI LIGBT. In addition, the BPSOI LIGBT effectively relieves the self-heating effect of the traditional SOI LIGBT.

Unified Analytical Model for SOI LDMOS With Electric Field Modulation

The unified analytical model is proposed for SOI LDMOS (Silicon On Insulator Lateral Double-diffused Metal Oxide Semiconductor) based on the electric field modulation in this paper for the first time. The analytical solutions of the surface electric field distributions and potential distributions are derived on the basis of the 2-D Poisson equation. The variation of the buried layer parameters modulates the surface electric field by the electric field modulation effect to optimize the surface electric field distribution of the device. Also, the simulation results obtained through the simulation software ISE are consistent with the expected results of the analytical model. This not only proves the feasibility of the electric field modulation theory, but also shows that the accurate analytical model will be of great guiding significance for designing and optimizing the same LDMOS based on SOI structures.

Novel SiC/Si heterojunction LDMOS with electric field modulation effect by reversed L-shaped field plate

A novel SiC/Si heterojunction lateral double-diffused metal-oxidesemiconductor (LDMOS) with a reversed L-shaped field plate and a stepped oxide layer has been proposed to improve the tradeoff between the breakdown voltage (BV) and specific on-resistance (Ron,sp). The reversed L-shaped field plate is applied to modulate electric field distribution to make the breakdown occur in the low electric field area (SiC/Si interface), which increases the BV and decreases the Ron,sp of the device. Furthermore, a stepped oxide layer is used to cover the Si drift region and reshape the lateral electric field distribution by introducing a new electric field peak, which consequently enhances the BV. The simulated results have indicated that the BV of this proposed SiC/Si LDMOS increased from 226 V and 720 V to 992 V compared with the conventional Si LDMOS and SiC LDMOS, respectively, while maintaining a low Ron,sp of 27.62 mΩ·cm2.

New Super-Junction LDMOS Breaking Silicon Limit by Multi-Ring Assisted Depletion Substrate

A novel super-junction (SJ) lateral double-diffused MOSFET with the multi-ring substrate (M-R SJ-LDMOS) is proposed for the first time. The substrate-assisted depletion (SAD) effect is eliminated by the n-type M-R to realize a balanced symmetric SJ with the low specific ON-resistance ( ${R}_{\text {on,sp}}$ ). Meanwhile, more uniform lateral and vertical electric field distributions are obtained under the surface and bulk electric field modulation effect, which leads to the enhancement of breakdown voltage (BV). The simulation results show that the BV of M-R SJ-LDMOS is increased by 427.2% and 81.2% in comparison with the conventional SJ-LDMOS and buffered step doping (BSD) SJ-LDMOS with the same drift region length, respectively. In addition, ${R}_{\text {on,sp}}$ of M-R SJ-LDMOS is reduced by 18.6% and 80.3% than that of BSD SJ-LDMOS and the conventional SJ-LDMOS. The figure-of-merit (FOM) of M-R SJ-LDMOS is 5.81 MW/cm2, which means the performance of M-R SJ-LDMOS is so excellent to break the silicon limit. +Moreover, the application of highly doped substrate ( ${3} \times {10}^{{15}}$ cm−3) in M-R SJ-LDMOS cuts the cost of substrate.

A Novel Kilovolts GaN Vertical Superjunction MOSFET With Trench Gate: Approach for Device Design and Optimization

In this paper, a gallium nitride (GaN) vertical superjunction (SJ) MOSFET with trench gate is proposed and studied by the TCAD simulation. In order to achieve the typical electric field ( $E$ -field) modulation effect by the P+/N/N+ structure in the conventional Si SJ-MOS, the P-GaN/unintentional doped (UID)-GaN/N+-GaN stack is alternatively used by taking into account the unavailability of P+-GaN. In this manner, the P-GaN and N+-substrate serve as the field-stop (FS) layers in the proposed GaN SJ-MOS. In the forward bias, the enhancement-mode function of the device is enabled by the gated side-wall and aperture composite channel that leads to a 1.47-V threshold voltage of the device. In the reverse bias, the breakdown of the device is governed by two mechanisms: 1) the punchthrough (PT) in the top P-GaN/N-drift junction due to the possible under design of the P-GaN thickness; 2) the avalanche breakdown triggered by high $E$ -field due to the possible under design of the bottom UID-GaN thickness. Hence, from the uniform $E$ -field distribution point of view, a device optimization approach for GaN vertical SJ-MOS is proposed. The hole and electron densities of P-GaN and N-drift are optimized to achieve a uniform $E$ -field distribution in the device both in the lateral and vertical directions, which is found to be $6 \times 10^{16}$ cm $^{-3}$ . Moreover, the thickness ratio of P-GaN/UID-GaN is designed to obtain an identical intrinsic breakdown for the top P-GaN/N-drift junction and bottom UID/N-drift region, which enables the maximum Baliga’s figure-of-merit (BFOM) of the device. The concept of device design and optimization is of great interests for GaN vertical device for over kilovolts applications.

Analytical model of buried air partial SOI LDMOS

A two-dimensional analytical model has been proposed for the Air Partial Silicon-On-Insulator (APSOI) LDMOS in this paper for the first time. The analytical solutions for the device are derived on the basis of the two-dimensional Poisson equation. An electric field modulation model that takes into account both the lateral and vertical electric field is proposed. The surface electric field is modulated through the variation of buried layer parameters with electric field modulation effect. Under the same simulation parameters, the breakdown voltage of APSOI LDMOS is 140% higher than that of traditional SOI and 93% higher than that of the traditional Silicon-On-Insulator structure with Step-Doped Drift region (SDDSOI). Also, it has been researched that the role of the key structural parameter in device performance is consistent with the expected results of the model, which proves that the effectiveness of electric field modulation effect and our model has guiding significance for device parameter optimization.

Analytical Models for the electric field and potential of AlGaN/GaN HEMT with partial silicon doping

Here, we study the mechanism of AlGaN/GaN HEMT with the partial silicon doping in the AlGaN layer under reverse bias and propose a two-dimensional analytic model for this device. The local density of two-dimensional electron gas (2DEG) increase at the interface between the AlGaN and GaN buffer due to partial silicon positive charge. And a new electric field peak is introduced by electric field modulation effect, which makes the electric field distribution of the channel surface more uniform and increases the breakdown voltage of the device. An analytical expression for the electric field and potential distribution of the channel is obtained, based on the two-dimensional Poisson's equation with appropriate boundary conditions. With this model, we explain the effects of silicon doping concentration and doping length on channel potential and electric field distribution in detail. By comparing the results obtained by the analytical model with the simulation results of Silvaco TCAD software, the numerical results and simulation results mostly match which verifies the validity of the model and provides a reference to model other AlGaN/GaN HEMTs.

Super junction LDMOS with P-trench and stepped buried oxide layer for high performance

In this paper, a new silicon-on-insulator superjunction lateral double-diffused MOSFET (SOI SJLDMOS) with a p-trench layer and stepped buried oxide, is investigated using 3D numerical simulation. The p-trench layer and stepped buried oxide distinguish it from a conventional SOI SJLDMOS. The etched buried oxide layer, with its stepped buried -oxide structure, which facilitates a more even electric field distribution via the electric field modulation effect, increases the breakdown-voltage (BV). Furthermore, the p-trench layer improves the doping concentration through compensation depletion, which further decreases the specific on-resistance (Ron,sp). The simulation indicates that the new device has a higher BV (increased by 29%) than the conventional SOI SJLDMOS. At the same time, Ron,sp decreases by 20% for the on-state for a given drift-region length.

Novel lateral double-diffused MOSFET with folded silicon and high-permittivity dielectric breaking silicon limit

A novel folded-accumulation LDMOS (FALDMOS) employing high-permittivity (HK) material as the partial field dielectric (HK-FALDMOS) is proposed and investigated by simulation. The device features the high-k dielectric partially replacing conventional SiO2 as the field oxide covering partial drift region and the gate electrode extending to the drain electrode. In the ON-state, the majority-carrier accumulation effect of HK-FALDMOS is more intense than that of FALDMOS, which is attributed to the larger capacitance of high-k film with the same dielectric thickness. Besides, a higher doping concentration in drift region I is obtained due to the electric field modulation effect resulting from the employed high-k film, which further reduces the specific on-resistance (Ron,sp) of the drift region I. The breakdown voltage (BV) declines slightly with the increase of permittivity of high-k film. Simulation results show that the proposed HK-FALDMOS has best-in-class Ron,sp-BV performance (9.9 mΩ mm2 with BV of 44.9 V when the relative permittivity of high-k is 8), which breaks the silicon limit of LDMOS.

Positive Column of a High-Modulation Depth Discharge Current Without Stepwise Ionization

The positive column of a gas discharge in helium is investigated for high-modulation-depth discharge current without stepwise ionization. The electron energy distribution function for different discharge current oscillation phases, the electron concentration, and the longitudinal electric field strength are measured in helium gas-discharge plasma. The electric field modulation effect and the change of the electron energy distribution function over the period at frequencies less than the reciprocal ambipolar diffusion time are detected.