Zero Temperature Coefficient of Current Gain Cutoff Frequency and Maximum Oscillation Frequency for Various SOI and Si Bulk MOSFETs

In this letter, a high breakdown voltage GaN HEMT device fabricated on semi-insulating self-standing GaN substrate is presented. High quality AlGaN/GaN epilayer was grown on self-standing GaN substrate by metal organic chemical vapor deposition. A 0.8μm gate length GaN HEMT device was fabricated with oxygen plasma treatment. By using oxygen plasma treatment, gate forward working voltage is increased, and a breakdown voltage of more than 170V is demonstrated. The measured maximum drain current of the device is larger than 700 mA/mm at 4V gate bias voltage. The maximum transconductance of the device is 162 mS/mm. In addition, high frequency performance of the GaN HEMT device is also obtained. The current gain cutoff frequency and power gain cutoff frequency are 19.7 GHz and 32.8 GHz, respectively. A high fT-LG product of 15.76 GHzμm indicating that homoepitaxy technology is helpful to improve the frequency performance of the device.

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A Novel 4H-SiC MESFET with a Heavily Doped Region, a Lightly Doped Region and an Insulated Region

Micromachines ◽

10.3390/mi12050488 ◽

2021 ◽

Vol 12 (5) ◽

pp. 488

Author(s):

Hujun Jia ◽

Mengyu Dong ◽

Xiaowei Wang ◽

Shunwei Zhu ◽

Yintang Yang

Keyword(s):

Breakdown Voltage ◽

Direct Current ◽

Oscillation Frequency ◽

The Novel ◽

Saturation Current ◽

Excellent Performance ◽

Maximum Oscillation Frequency ◽

Power Added Efficiency ◽

Novel Structure ◽

Heavily Doped

A novel 4H-SiC MESFET was presented, and its direct current (DC), alternating current (AC) characteristics and power added efficiency (PAE) were studied. The novel structure improves the saturation current (Idsat) and transconductance (gm) by adding a heavily doped region, reduces the gate-source capacitance (Cgs) by adding a lightly doped region and improves the breakdown voltage (Vb) by embedding an insulated region (Si3N4). Compared to the double-recessed (DR) structure, the saturation current, the transconductance, the breakdown voltage, the maximum oscillation frequency (fmax), the maximum power added efficiency and the maximum theoretical output power density (Pmax) of the novel structure is increased by 24%, 21%, 9%, 11%, 14% and 34%, respectively. Therefore, the novel structure has excellent performance and has a broader application prospect than the double recessed structure.

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Structures and microwave dielectric properties of Ti-doped CeO2 ceramics with a near-zero temperature coefficient of resonant frequency

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2020.157270 ◽

2021 ◽

Vol 854 ◽

pp. 157270

Author(s):

Zhijian Wang ◽

Ying Chen

Keyword(s):

Dielectric Properties ◽

Resonant Frequency ◽

Temperature Coefficient ◽

Microwave Dielectric Properties ◽

Zero Temperature ◽

Microwave Dielectric ◽

Doped Ceo2

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VERTICAL SCALING OF TYPE I InP HBT WITH FT > 500 GHZ

International Journal of High Speed Electronics and Systems ◽

10.1142/s0129156404002582 ◽

2004 ◽

Vol 14 (03) ◽

pp. 625-631 ◽

Cited By ~ 2

Author(s):

J. W. LAI ◽

W. HAFEZ ◽

M. FENG

Keyword(s):

Heterojunction Bipolar Transistors ◽

High Speed ◽

Impact Ionization ◽

Cutoff Frequency ◽

Current Gain ◽

Vertical Scaling ◽

Physical Parameters ◽

Type I ◽

Peak Current Density ◽

Rf Performance

We have fabricated the high-speed InP/InGaAs -based single heterojunction bipolar transistors (SHBTs) with current gain cutoff frequency, fT from 166GHz to over 500GHz by the approach of vertical scaling. Collector thickness is reduced from 3000Å to 750Å and the peak current density is increased up to 1300kA/cm2. In this paper, device rf performance has been compared with respect to materials with different vertical dimensions. The scaling limitation is also studied by analytical approach. The extracted physical parameters suggest that the parasitic emitter resistance is the major limit on further enhancing ultra-scaled HBT intrinsic speed due to the associated RECBC delay. The cut-off frequency of a 500Å collector SHBT has been measured and the results indicate a dramatic drop on fT, supporting the conclusion projected by model analysis. It is also commented that for deeply downscaled HBTs, impact ionization could be another degrading mechanism limits device bandwidth.

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