免镇流电阻的非均匀发射极指间距设计对多指功率双极晶体管射频功率性能的改善（英文）

对不添加镇流电阻的非均匀发射极条间距的多发射极条异质结双极晶体管(HBT)的射频功率性能和表面温度分布进行了测量,并与常规采用镇流电阻的多发射极条功率HBT进行了比较。实验结果表明,对具有非均匀发射极条间距的多发射极条HBT,采用USQFITMS红外测量系统测得的最高表面温度、温度分布均匀性以及采用射频测量系统测得的射频功率增益和功率附加效率,分别低于、好于和高于具有镇流电阻的多发射极条功率HBT的情况。这些结果的取得,得益于采用非均匀发射极条间距改善了多发射极条HBT的热电正反馈和不同发射极条之间的热耦合,以及摆脱了传统HBT加镇流电阻带来的对射频功率性能的负作用。     

基于热电模型的多发射极功率HBTs非均匀镇流电阻设计

在考虑发射结电压随温度的变化和发射极加入镇流电阻的情况下,给出简化的三维热电模型,用以计算功率HBT芯片表面温度分布.分析表明,对于采用均匀发射极镇流电阻设计的功率HBT,芯片中心发射极条温度最高,严重限制了器件的功率处理能力.因此提出非均匀发射极镇流电阻设计方案,并以12指Si0.8Ge0.2HBT为例,详细地给出非均匀发射极镇流电阻设计流程.结果表明,在总发射极镇流电阻阻值(各指发射极镇流电阻并联值)不变的情况下,非均匀发射极镇流电阻设计与传统的均匀设计相比,芯片中心结温显著降低,芯片表面温度趋于一致.还发现当各指发射极镇流电阻阻值从芯片边缘到中心按指数形式分布时,功率HBT的芯片表面温度更容易趋于均匀,大大提高了HBT的功率处理能力,为功率HBT的设计提供了指导.     

基于热电模型的多发射极功率HBTs非均匀镇流电阻设计

在考虑发射结电压随温度的变化和发射极加入镇流电阻的情况下,给出简化的三维热电模型,用以计算功率HBT芯片表面温度分布.分析表明,对于采用均匀发射极镇流电阻设计的功率HBT,芯片中心发射极条温度最高,严重限制了器件的功率处理能力.因此提出非均匀发射极镇流电阻设计方案,并以12指Si0.8Ge0.2HBT为例,详细地给出非均匀发射极镇流电阻设计流程.结果表明,在总发射极镇流电阻阻值(各指发射极镇流电阻并联值)不变的情况下,非均匀发射极镇流电阻设计与传统的均匀设计相比,芯片中心结温显著降低,芯片表面温度趋于一致.还发现当各指发射极镇流电阻阻值从芯片边缘到中心按指数形式分布时,功率HBT的芯片表面温度更容易趋于均匀,大大提高了HBT的功率处理能力,为功率HBT的设计提供了指导.     

非均匀条间距结构功率SiGe HBT

成功研制出非均匀发射极条间距功率SiGe异质结双极晶体管(HBT)用以改善功率器件热稳定性.实验结果表明,在相同的工作条件下,与传统的均匀发射极条间距HBT相比,非均匀结构HBT的峰值结温降低了22K.在不同偏置条件下,非均匀结构SiGe HBT均能显著改善芯片表面温度分布的非均匀性.由于峰值结温的降低以及芯片表面温度分布非均匀性的改善,采用非均匀发射极条间距结构的功率SiGe HBT可以工作在更高的偏置条件下,具有更高的功率处理能力.     

非均匀条间距结构功率SiGe HBT

成功研制出非均匀发射极条间距功率SiGe异质结双极晶体管(HBT)用以改善功率器件热稳定性.实验结果表明,在相同的工作条件下,与传统的均匀发射极条间距HBT相比,非均匀结构HBT的峰值结温降低了22K.在不同偏置条件下,非均匀结构SiGe HBT均能显著改善芯片表面温度分布的非均匀性.由于峰值结温的降低以及芯片表面温度分布非均匀性的改善,采用非均匀发射极条间距结构的功率SiGe HBT可以工作在更高的偏置条件下,具有更高的功率处理能力.     

改善多指HBT热稳定性的非均匀指间距技术

建立了多发射极指功率SiGe HBT的热电反馈模型,研究了发射极指间距的变化对多指功率SiGe HBT表面温度分布的影响.在此基础上,提出了发射极指间距的非均匀化优化技术.在不同偏置下,对具有均匀间距和非均匀间距的多指HBT各指之间的温度分布进行模拟.结果表明,具有非均匀指间距结构的SiGe HBT峰值温度明显下降,各指之间的温度分布均匀性得到加强,这是传统均匀指间距技术无法比拟的,显示了非均匀指间距优化技术的优越性.     

改善不同环境温度下SiGe HBT热稳定性的技术

提出了发射极非均匀指间距技术以增强多发射极指SiGe HBT在不同环境温度下的热稳定性。通过建立热电反馈模型对采用发射极非均匀指间距技术的SiGe HBT进行热稳定性分析,得到多发射极指上的温度分布。结果表明,与传统的均匀发射极指间距SiGe HBT相比,在相同的环境温度及耗散功率下,采用发射极非均匀指间距技术的SiGe HBT,其最高结温明显降低,热阻显著减小,温度分布更加均匀,有效地提高了多发射极指功率SiGe HBT在不同环境温度下的热稳定性。     

多发射极条功率SiGe HBT的热电耦合与优化设计

利用自洽迭代数值计算方法,对多发射极微波功率SiGe HBT芯片热电耦合特性进行了模拟和分析。结果表明,通过对晶体管发射极条长、条间距的调整,可以有效地改善芯片温度分布的不均匀性,提高晶体管的热稳定性和功率处理能力。     

基于有源镇流改善射频功率管的热稳定性

提出一种基于有源电路的基极镇流方案,用以解决射频功率晶体管的电流集中和热稳定性问题.采用传感器检测非均匀结温分布,后级相邻触发电路触发功率器件子单元基极和发射极之间的镇流MOS管,通过分流来缓解电流集中,进而完成器件子单元的过温保护.模拟结果表明,该方案可以有效地实现对功率器件的保护,与传统的无源镇流电阻方法相比,改进后的器件具有更优良的增益特性.单个有源镇流电路仅消耗功率6.5 mW,占用面积为2 530 μm2.     

硅微波功率器件二次发射极镇流研究

本文报道了采用多晶硅电阻和扩散电阻组合而成的复合镇流电阻对硅微波功率器件进行二次发射极镇流的实验结果．     

Amorphous-Si emitter heterojunction UHF power transistors for handytransmitter

A UHF silicon heterojunction bipolar power transistor with a heavily doped amorphous-silicon emitter is reported. The fabrication process utilized an improved glow discharge technique. The deposition rate of amorphous silicon is 0.3-0.4 Å/s, which is slower than that of conventional a-Si:H. The average carrier density in the amorphous-silicon film is estimated to be about 1.5×10¹⁹ cm^-3. The present device can deliver 4.0-W output power with 72% collector efficiency and 8.2-dB gain at 470 MHz for 9.0-V low supply voltage. These preliminary results make the use of n⁺ a-Si:H as a wide-bandgap emitter material for high-frequency and high-power heterojunction bipolar transistors (HBTs) very attractive     

基于斩波自动稳零运算放大器的激光器平均光功率控制

本文介绍了斩波自动稳零集成运算放大器中斩波技术和自动稳零的基本工作原理。利用这种放大器能够放大直流微弱信号(可以达到1PA)的特点，使用典型芯片ICL7650设计了在光纤数字通信系统中对光端机进行平均光功率控制的电路。实验表明光端机短时功率波动小于0.05dBm。     

Influence of polysilicon deposition on fabrication of power polysilicon emitter bipolar transistors

The aim was to fabricate a polysilicon emitter bipolar transistor for power applications. To this end, different polysilicon deposition steps compatible with the power bipolar technology and their influence on electrical characteristics were studied.<>     

Enhanced power cycling performance of IGBT modules with a reinforced emitter contact

A typical emitter contact of an IGBT consists of a front metallization and bond wires. In this study, the power cycling performance of a special emitter contact design is experimentally verified. The emitter contact includes a metal plate, which is Ag-sintered to the metallization and wire bonded on the top surface. Either Cu or Al bond wires were implemented. Power cycling tests were performed to investigate the performance of such IGBT modules. The results were very promising and a cycling lifetime was achieved, which is about 20 times higher than the lifetime of typical IGBT modules. For a better understanding of the experimental results, the electrical and thermal response of the IGBT modules were simulated by FEM. The results of this study, provide a key for high-reliability designs of the emitter contact of IGBT modules with superior power cycling capability.     

Output power measurement of photonic millimetre-wave andsub-millimetre-wave emitter at 100-800 GHz

A photonic millimetre-wave and sub-millimetre-wave emitter (PME) that uses a log-periodic antenna and a uni-travelling carrier photodiode has been fabricated and tested. The output power and spectra of the PME were measured with a Fourier transform spectrometer and a bolometer at 100-800 GHz in a low-power excitation condition. The extrapolated output power with 15 mA photocurrent is several tens of microWatts in the 300-600 GHz range     

Thermal behavior depending on emitter finger and substrateconfigurations in power heterojunction bipolar transistors

Analytical and experimental results are used to investigate thermal behavior depending on the emitter-finger area and substrate thickness in multifinger heterojunction bipolar transistors (HBT's). The temperature distributions along the depth direction of the substrate are obtained from a three-dimensional (3-D) analysis. The calculated results show a 3-D effect which depends upon the emitter finger area. This effect weakens with increasing the emitter-finger area. As the effect weakens, thinning the substrate effectively reduces the junction temperature (thermal resistance). This is verified by the measured results obtained from a simple thermal-resistance measurement     

Common emitter breakdown

A theory of the current-voltage characteristics with grounded emitter and open base is developed in a first approximation form. The results show the typical negative resistance region characteristic of theseI-Vcurves, and the theory indicates the important parameters which control this negative resistance. The containment of the emitter current with subsequent development of "hot spots" on the transistor becomes easily understood. Experimental evidence of the importance of localized breakdown spots in common emitter breakdown is presented.     

The emitter tetrode

If two ohmic contacts are made to the thin emitter region of a transistor in the form of a ring around the periphery and a dot in the center, it is possible to vary the ratio of the emitted current density under the center dot to the emitted density under the ring by passing a transverse current radially through the emitter region. This makes it possible to reduce the surface losses in such a transistor esentially to zero, at some expense of increased base resistance. Such a controllable alpha makes possible feedback stabilization into an independent terminal. The essential theory of operation and experimental verification of the calculations are shown and discussed.