An emitter self-aligned InP-based single heterojunction bipolar transistor with a cutoff frequency （fT） of 162GHz is reported. The emitter size is 0.8μm × 12μm, the maximum DC gain is 120, the offset voltage is 0.10V,and the typical breakdown voltage at Ic = 0. 1μA is 3.8V. This device is suitable for high-speed low-power applications,such as OEIC receivers and analog-to-digital converters.
研究了蓝宝石衬底 Al Ga N/Ga N共栅共源器件的特性。该器件包括栅长 0 .8μm共源器件与栅长 1 μm的共栅器件。研究表明 ,共栅共源器件的第二栅压对的器件饱和电流与跨导有明显的调制作用 ,容易实现功率增益控制。与共源器件相比 ,共栅共源器件在微波特性上 f T 大约 9GHz,比共源器件稍小 ,但是具有较低的反馈 ,显著增加的功率资用增益及较高的端口阻抗 ,与共源器件相比 ,稳定性更好 ,可以避免振荡的产生 ,结合 Ga N的高功率特性 Ga
This paper focuses on how to reduce the gate leakage current caused by plasma dry etching. X-ray photoelectron spectroscopy （XPS） is employed to measure the AlGaN surface before and after etching. N vacancies are introduced, which cause that gate currents are not dominated by the thermal electron emission mechanism. N vacancies enhance the tunneling effect and reduce the Schottky barrier height as n-type doped in the etched AIGaN surface.A post-gate process for AlGaN/GaN HEMTs,annealing at 400℃ in a nitrogen ambient for 10min is introduced. After annealing, Ni atoms of gate metal reacted with Ga atoms of AlGaN, and N vacancies were reduced. The reverse leakage decreased by three orders of magnitude,the forward turn-on voltage increased and the ideality factor reduced from 3.07 to 2.08.
The accurate extraction of AlGaN/GaN HEMT small-signal models, which is an important step in largesignal modeling, can exactly reflect the microwave performance of the physical structure of the device. A new method of extracting the parasitic elements is presented, and an open dummy structure is introduced to obtain the parasitic capacitances. With a Schottky resistor in the gate, a new method is developed to extract Rg. In order to characterize the changes of the depletion region under various drain voltages, the drain delay factor is involved in the output conductance of the device. Compared to the traditional method, the fitting of S 11 and S 22 is improved, and fT and fmax can be better predicted. The validity of the proposed method is verified with excellent correlation between the measured and simulated S-parameters in the range of 0.1 to 26.1 GHz.
