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Theoretical analytic model for RESURF AlGaN/GaN HEMTs

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Chinese Physics B 2019年第2期28卷 395-399页

作者： Hao Wu Bao-Xing Duan Luo-Yun Yang Yin-Tang Yang key laboratory of the ministry of education for wide band-gap semiconductor materials and devices Xidian University

In this paper, we propose a two-dimensional(2D) analytic model for the channel potential and electric field distribution of the RESURF AlGaN/GaN high electron mobility transistors(HEMTs). The model is constructed by two-dimensional Poisson's equation with appropriate boundary conditions. In the RESURF AlGaN/GaN HEMTs, we utilize the RESURF effect generated by doped negative charge in the AlGaN layer and introduce new electric field peaks in the device channels,thus, homogenizing the distribution of electric field in channel and improving the breakdown voltage of the device. In order to reveal the influence of doped negative charge on the electric field distribution, we demonstrate in detail the influences of the charge doping density and doping position on the potential and electric field distribution of the RESURF AlGaN/GaN HEMTs with double low density drain(LDD). The validity of the model is verified by comparing the results obtained from the analytical model with the simulation results from the ISE software. This analysis method gives a physical insight into the mechanism of the AlGaN/GaN HEMTs and provides reference to modeling other AlGaN/GaN HEMTs device.

关键词： RESURF AlGaN/GaN HEMTs two-dimensional analytic model potential distribution electric field distribution

Early effect modeling of silicon-on-insulator SiGe heterojunction bipolar transistors

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Chinese Physics B 2011年第5期20卷 444-449页

作者：徐小波张鹤鸣胡辉勇马建立 key laboratory of ministry of education for wide band-gap semiconductor materials and devices School of MicroelectronicsXidian University

Silicon germanium （SiGe） heterojunction bipolar transistor （HBT） on thin silicon-on-insulator （SOI） has recently been demonstrated and integrated into the latest SOI BiCMOS technology. The Early effect of the SOI SiGe HBT is analysed considering vertical and horizontal collector depletion, which is different from that of a bulk counterpart. A new compact formula of the Early voltage is presented and validated by an ISE TCAD simulation. The Early voltage shows a kink with the increase of the reverse base-collector bias. Large differences are observed between SOI devices and their bulk counterparts. The presented Early effect model can be employed for a fast evaluation of the Early voltage and is useful to the design, the simulation and the fabrication of high performance SOI SiCe devices and circuits.

关键词： heterojunction bipolar transistor (HBT) SiGe silicon-on-insulator Early effect

A 0.18μm CMOS dual-band low power low noise amplifier for a global navigation satellite system

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Journal of semiconductors 2010年第12期31卷 94-100页

作者：李兵庄奕琪李振荣靳刚 key laboratory of the ministry of education for wide band-gap semiconductor materials and devices School of MicroelectronicsXidian University

This paper presents a dual-band low noise amplifier for the receiver of a global navigation satellite system. The differences between single band and multi-band design methods are discussed. The relevant parameter analysis and the details of circuit design are presented. The test chip was implemented in a TSMC 0.18 μm 1P4M RF CMOS process. The LNA achieves a gain of 16.8 dB/18.9 dB on 1.27 GHz/1.575 GHz. The measured noise figure is around 1.5-1.7 dB on both bands. The LNA consumes less than 4.3 mA of current from a 1.8 V power supply. The measurement results show consistency with the design. And the LNA can fully satisfy the demands of the GNSS receiver.

关键词： CMOS low noise amplifier low power dual-band noise figure GPS RF frontend

A 9.8-mW 1.2-GHz CMOS frequency synthesizer with a low phase-noise LC-VCO and an I/Q frequency divider

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Journal of semiconductors 2011年第7期32卷 108-114页

作者：李振荣庄奕琪李兵靳刚 key laboratory of the ministry of education for wide band-gap semiconductor materials and devices School of MicroelectronicsXidian University

A 1.2 GHz frequency synthesizer integrated in a RF receiver for Beidou navigation is implemented in standard 0.18μm CMOS technology.A distributed biased varactor LC voltage-controlled oscillator is employed to achieve low tuning sensitivity and optimized phase noise performance.A high-speed and low-switching-noise divider-by-2 circuit based on a source-coupled logic structure is adopted to generate a quadrature（I/Q） local oscillating signal.A high-speed 8/9 dual-modulus prescaler（DMP）,a programmable-delay phase frequency detector without dead-zone problem,and a programmable-current charge pump are also integrated into the frequency synthesizer. The frequency synthesizer demonstrates an output frequency from 1.05 to 1.30 GHz,and the phase noise is-98.53 dBc/Hz at 100-kHz offset and -121.92 dBc/Hz at 1-MHz offset from the carrier frequency of 1.21 GHz. The power dissipation of the core circuits without the output buffer is 9.8 mW from a 1.8 V power *** total area of the receiver is 2.4×1.6 mm^2.

关键词： Beidou receiver frequency synthesizer voltage-controlled oscillator quadrature output divider phase noise

The low-temperature mobility of two-dimensional electron gas in AlGaN/GaN heterostructures

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Chinese Physics B 2008年第7期17卷 2689-2695页

作者：张金风毛维张进城郝跃 key laboratory of ministry of education for wide band-gap semiconductor materials and devices Microelectronics InstituteXidian University

To reveal the internal physics of the low-temperature mobility of two-dimensional electron gas （2DEG） in Al- GaN/GaN heterostructures, we present a theoretical study of the strong dependence of 2DEG mobility on Al content and thickness of AlGaN barrier layer. The theoretical results are compared with one of the highest measured of 2DEG mobility reported for AlGaN/GaN heterostructures. The 2DEG mobility is modelled as a combined effect of the scat- tering mechanisms including acoustic deformation-potential, piezoelectric, ionized background donor, surface donor, dislocation, alloy disorder and interface roughness scattering. The analyses of the individual scattering processes show that the dominant scattering mechanisms are the alloy disorder scattering and the interface roughness scattering at low temperatures. The variation of 2DEG mobility with the barrier layer parameters results mainly from the change of 2DEG density and distribution. It is suggested that in AlGaN/GaN samples with a high Al content or a thick AlGaN layer, the interface roughness scattering may restrict the 2DEG mobility significantly, for the AlGaN/GaN interface roughness increases due to the stress accumulation in AlGaN layer.

关键词： two-dimensional electron gas mobility AlGaN/GaN heterostructures interface roughness

Quantum compact model for thin-body double-gate Schottky barrier MOSFETs

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Chinese Physics B 2008年第8期17卷 3077-3082页

作者：栾苏珍刘红侠 School of Microelectronics Xidian University key laboratory of ministry of education for wide band-gap semiconductor materials and devices

Nanoscale Schottky barrier metal oxide semiconductor field-effect transistors （MOSFETs） are explored by using quantum mechanism effects for thin-body devices. The results suggest that for small nonnegative Schottky barrier heights, even for zero barrier height, the tunnelling current also plays a role in the total on-state current. Owing to the thin body of device, quantum confinement raises the electron energy levels in the silicon, and the tradeoff takes place between the quantum confinement energy and Schottky barrier lowering （SBL）. It is concluded that the inclusion of the quantum mechanism effect in this model, which considers an infinite rectangular well with a first-order perturbation in the channel, can lead to the good agreement with numerical result for thin silicon film. The error increases with silicon thickness increasing.

关键词： Schottky barrier quantum mechanism effects effective mass electron density

Investigation of current transport parameters of Ti/4H-SiC MPS diode with inhomogeneous barrier

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Chinese Physics B 2011年第5期20卷 353-358页

作者：宋庆文张玉明张义门陈丰平汤晓燕 School of Microelectronics Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices of Ministry of EducationXidian University

The current transport parameters of 4H-SiC merged PiN Schottky （MPS） diode are investigated in a temperature range of 300-520 K. Evaluation of the experimental current-voltage （I-V） data reveals the decrease in Schottky barrier height Φb but an increase in ideality factor n, with temperature decreasing, which suggests the presence of an inhomogeneous Schottky barrier. The current transport behaviours are analysed in detail using the Tung＇s model and the effective area of the low barrier patches is extracted. It is found that small low barrier patches, making only 4.3% of the total contact, may significantly influence the device electrical characteristics due to the fact that a barrier height of 0.968 eV is much lower than the average barrier height 1.39 eV. This shows that ion implantation in the Schottky contact region of MPS structure may result in a poor Ti/4H-SiC interface quality. In addition, the temperature dependence of the specific on-resistance （Ron-sp）, T^2.14, is determined between 300 K and 520 K, which is similar to that predicted by a reduction in electron mobility.

关键词： 4H-SiC MPS barrier inhomogeneity specific on-resistance

Characteristics and parameter extraction for NiGe/n-type Ge Schottky diode with variable annealing temperatures

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Chinese Physics B 2010年第5期19卷 530-535页

作者：刘红侠吴笑峰胡仕刚石立春 School of Microelectronics Xidian UniversityKey Laboratory for Wide Band-Gap Semiconductor Materials and Devices of Ministry of Education

Current transport mechanism in Ni-germanide/n-type Ge Schottky diodes is investigated using current-voltage characterisation technique with annealing temperatures from 300 ℃ to 500℃. Based on the current transport model, a simple method to extract parameters of the NiGe/Ge diode is presented by using the I-V characteristics. Parameters of NiGe/n-type Ge Schottky diodes fabricated for testing in this paper are as follows： the ideality factor n, the series resistance Rs, the zero-field barrier height Фb0, the interface state density Dit, and the interracial layer capacitance Ci. It is found that the ideality factor n of the diode increases with the increase of annealing temperature. As the temperature increases, the interface defects from the sputtering damage and the penetration of metallic states into the Ge energy gap are passivated, thus improving the junction quality. However, the undesirable crystallisations of Ni-germanide are observed together with NiGe at a temperature higher than 400℃. Depositing a very thin （-1 nm） heavily Ge-doped n＋ Ge intermediate layer can improve the NiGe film morphology significantly.

关键词： NiGe Schottky diode barrier height parameter extraction

Modeling and understanding of the frequency dependent HPM upset susceptibility of the CMOS inverter

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Science China(Information Sciences) 2015年第8期58卷 182-192页

作者： YU XinHai CHAI ChangChun LIU Yang YANG YinTang key laboratory of ministry of education for wide band-gap semiconductor materials and devices School of Microelectronics Xidian University

In this paper, we interpret and, for the first time, model a frequency dependent high-power microwave(HPM) upset susceptibility. We constructed the analytical models of the total amount of injected charges N inj, the excess carrier density distribution in P-Substrate, and the frequency dependent HPM upset susceptibility level. The models are validated by simulated results and experimental data, respectively. Results reveal that N inj is proportional to fαwhile the exponent α should be adjusted to-0.525. The excess carrier density distribution behaves the frequency dependence as well; the dependence is attributable to the fact that the AC field within the CMOS inverter varies too rapidly for the carriers to follow at high frequency. Meanwhile,the HPM upset susceptibility level is a decreasing function of f. The f dependent HPM upset susceptibility model is verified to be reliable and able to quickly estimate the susceptibility level of CMOS inverter considering IC technology, layout parameters, pulse properties, and operating environment simultaneously. Besides, the empirical formula P = A · fαis proposed to provide instant estimation to the HPM upset power threshold. In conclusion, by aid of the analytical model, we acquired the influence of the layout parameter LB on the HPM susceptibility and demonstrated that the CMOS inverter with minor LB is more susceptible to HPM.

关键词： high power microwave frequency upset CMOS analytical model