Compared with gunn diode, mesfet has the advantage of high efficiency, flexible design and easy to integrate . the two ports negative resistance oscillating network is analyzed and an extremum-line model of microwave transistor oscillating network output impedance is developed mesfet较之gunn二极管在vco电路中有效率高、设计灵活性、便于集成等优点，所以本文着重介绍了变容管调谐微带结构mesfetvco的研制工作。
It has been shown that the performance of sige heterojunction bipolar transistor ( sige hbt ) in high frequency is much better than that of si bipolar junction transistor ( si bjt ), and is better than that of algaas / gaas metal semiconductor field effect transistor ( algaas / gaas mesfet ) in some aspects sige异质结双极晶体管（sigehbt）的高频性能大大优于si双极晶体管（sibjt），并在某些方面优于algaas/gaasmesfet，所以sigehbt具有广阔的应用前景。
The optical effect on the uniformity of mesfet threshold voltage is studied . results show that optical radiation enhances the drain-source current of the gaas mesfet, and makes the threshold voltage to move toward negative direction . optical radiation enhances the uniformity of mesfet threshold voltage 本文研究了光照对阈值电压均匀性的影响，观察到在光照条件下，耗尽型mesfet的沟道电流增加，阈值电压向负方向增加，光照提高了阈值电压的均匀性。
The optical effect on the uniformity of mesfet threshold voltage is studied . results show that optical radiation enhances the drain-source current of the gaas mesfet, and makes the threshold voltage to move toward negative direction . optical radiation enhances the uniformity of mesfet threshold voltage 本文研究了光照对阈值电压均匀性的影响，观察到在光照条件下，耗尽型mesfet的沟道电流增加，阈值电压向负方向增加，光照提高了阈值电压的均匀性。
The optical effect on the uniformity of mesfet threshold voltage is studied . results show that optical radiation enhances the drain-source current of the gaas mesfet, and makes the threshold voltage to move toward negative direction . optical radiation enhances the uniformity of mesfet threshold voltage 本文研究了光照对阈值电压均匀性的影响，观察到在光照条件下，耗尽型mesfet的沟道电流增加，阈值电压向负方向增加，光照提高了阈值电压的均匀性。
These devices include light-emitting diode, laser diode, uv-detector, mesfet, hemt, modfet etc . since 1990's, on the basis of advanced techniques of materials preparation, gan-based leds and lds were achieved successfully, and leds on sapphire substrates have already been commercialized 九十年代以来，在先进制备技术的基础上，gan基leds和lds分别研制成功，其中蓝宝石衬底上的leds已经进入了商品化。gan基微电子器件也得到了广泛的关注，取得了一定的研究进展。
The device structure and physical models of 4h-sic mosfet and mesfet are built and the properties are simulated with the use of medici software . the influence of the temperature and structure parameter on the device's properties is summarized indicates that no negative resistance exists in breakdown property and the breakdown voltage is up to 85v and 209v separately . the maximum power density of 4h-sic mesfet is as high as 19.22w / mm . at the same time, the processes of sic field-effect transistor is studied and the fabrication processes suitable to sic mosfet are developed . 论文分析建立了4h-sicmosfet和mesfet器件的结构模型和物理模型，采用二维器件模拟软件medici对4h-sicmosfet和mesfet的输出特性进行了模拟分析，研究了温度和结构参数对器件特性的影响，表明两种器件的击穿特性均没有负阻现象，击穿电压分别达到85v和209v，由此得到4h-sicmesfet最大功率密度可达到19.22wmm；同时，研究了sic场效应晶体管的制作工艺，初步得到了一套制造sicmosfet器件的制造工艺流程，研制出了4h-sicmosfet器件。
The device structure and physical models of 4h-sic mosfet and mesfet are built and the properties are simulated with the use of medici software . the influence of the temperature and structure parameter on the device's properties is summarized indicates that no negative resistance exists in breakdown property and the breakdown voltage is up to 85v and 209v separately . the maximum power density of 4h-sic mesfet is as high as 19.22w / mm . at the same time, the processes of sic field-effect transistor is studied and the fabrication processes suitable to sic mosfet are developed . 论文分析建立了4h-sicmosfet和mesfet器件的结构模型和物理模型，采用二维器件模拟软件medici对4h-sicmosfet和mesfet的输出特性进行了模拟分析，研究了温度和结构参数对器件特性的影响，表明两种器件的击穿特性均没有负阻现象，击穿电压分别达到85v和209v，由此得到4h-sicmesfet最大功率密度可达到19.22wmm；同时，研究了sic场效应晶体管的制作工艺，初步得到了一套制造sicmosfet器件的制造工艺流程，研制出了4h-sicmosfet器件。
Especially, mesfet devices fabricated on lec si-gaas substrate have been adopted into very large-scale integration ( vlsi ) and monolithic microwave integrated circuit ( mmic ) extensively . therefore, it is necessary to study the influence of defects in substrate material of lec si-gaas on performance of mesfet to meet the need of design and fabrication of gaas ic 以液封直拉半绝缘gaas为衬底的金属半导体场效应晶体管(mesfet)器件是超大规模集成电路和单片微波集成电路广泛采用的器件结构，因此研究lec法生长si-gaas(lecsi-gaas)衬底材料特性对mesfet器件性能的影响，对gaas集成电路和相关器件的设计及制造是非常必要的。
Especially, mesfet devices fabricated on lec si-gaas substrate have been adopted into very large-scale integration ( vlsi ) and monolithic microwave integrated circuit ( mmic ) extensively . therefore, it is necessary to study the influence of defects in substrate material of lec si-gaas on performance of mesfet to meet the need of design and fabrication of gaas ic 以液封直拉半绝缘gaas为衬底的金属半导体场效应晶体管(mesfet)器件是超大规模集成电路和单片微波集成电路广泛采用的器件结构，因此研究lec法生长si-gaas(lecsi-gaas)衬底材料特性对mesfet器件性能的影响，对gaas集成电路和相关器件的设计及制造是非常必要的。
