集成双极型晶体管模型参数的总体优化提取

本文给出了采用分步式总体优化提取双极GP模型直流参数的方法,其中包括双向目标函数的建立、参数提取等级的划分和初值的确定,以及模型参数的全城总体提取。文中介绍了用该法编制的程序及其成功的应用。     

基于漏区边界曲率分析的射频RESURF LDMOS耐压与导通电阻优化

分析了漏区边界曲率半径与射频RESURF LDMOS击穿电压的关系,指出漏区边界的弯曲对RESURF技术的效果具有强化作用.理论分析与模拟结果表明,满足RESURF条件时,提高漂移区掺杂浓度或掺杂深度的同时相应减小漏区边界的曲率半径,可以在维持击穿电压不变的前提下,明显降低导通电阻.     

集成电路可制造性经济学模型（一）—广义前道工序模型

文章从集成电路（ＩＣ）发展规律出发，提出了可制造性设计的必要性和迫切性，并提出了基于可制造性设计的ＩＣ前道工序成本模型，为实现成本驱动设计的自动化和最优化打下必要的基础。     

^（60）Co γ-rays irradiation effect in DC performance of AlGaN/GaN high electron mobility transistors

Unpassivated/passivated AlGaN/GaN high electron mobility transistors （HEMTs） were exposed to 1.25 MeV 60Co γ-rays at a dose of 1 Mrad（Si）. The saturation drain current of the unpassivated devices decreased by 15% at 1 Mrad γ-dose, and the maximal transconductance decreased by 9.1% under the same condition; more- over, either forward or reverse gate bias current was significantly increased, while the threshold voltage is relatively unaffected. By sharp contrast, the passivated devices showed scarcely any change in saturation drain current and maximal transconductance at the same γ dose. Based on the differences between the passivated HEMTs and un- passivated HEMTs, adding the C–V measurement results, the obviously parameter degradation of the unpassivated AlGaN/GaN HEMTs is believed to be caused by the creation of electronegative surface state charges in sourcegate spacer and gate–drain spacer at the low dose （1 Mrad）. These results reveal that the passivation is effective in reducing the effects of surface state charges induced by the 60Co γ-rays irradiation, so the passivation is an effective reinforced approach.     

Surface morphology of [110] a-plane GaN growth by MOCVD on [1■02] r-plane sapphire

Nonpolar a-plane [110] GaN has been grown on r-plane [1■02] sapphire by MOCVD, and investigated by high resolution X-ray diffraction and atomic force microscopy. As opposed to the c-direction, this particular orientation is non-polar, and it avoids polarization charge, the associated screening charge and the consequent band bending. Both low-temperature GaN buffer and high-temperature AlN buffer are used for a-plane GaN growth on r-plane sapphire, and the triangular pits and pleat morphology come forth with different buffers, the possible reasons for which are discussed. The triangular and pleat direction are also investigated. A novel modulate buffer is used for a-plane GaN growth on r-plane sapphire, and with this technique, the crystal quality has been greatly improved.     

用MOCVD在r面蓝宝石衬底上生长的a面GaN的独特电学性质研究

Nonpolar （1120） a-plane GaN films have been grown by low-pressure metal-organic vapor deposition on r-plane （1102） sapphire substrate. The structural and electrical properties of the a-plane GaN films are investigated by high-resolution X-ray diffraction （HRXRD）, atomic force microscopy （AFM） and van der Pauw Hall measurement. It is found that the Hall voltage shows more anisotropy than that of the c-plane samples; furthermore, the mobility changes with the degree of the van der Pauw square diagonal to the c direction, which shows significant electrical anisotropy. Further research indicates that electron mobility is strongly influenced by edge dislocations.     

60Co-γ射线辐射对AlGaN/GaN HEMT器件直流特性的影响

采用1.25Mev 60Co γ射线辐射源对钝化前后的AlGaN/GaN HEMT器件进行了1Mrad(Si)的总剂量辐射,实验发现：1Mrad总剂量辐射后未钝化器件的饱和漏电流和最大跨导分别下降了15%和9.1%,而且正向和反向栅电流明显增加,但是阈值电压几乎没有发生变化。相反的,同样的累积剂量下,钝化器件的饱和漏电流和最大跨导却基本没变。通过对钝化前后器件的不同辐射反应以及C-V测试的分析表明,栅-源和栅-漏间隔区辐射感生表面态负电荷的产生是低剂量下AlGaN/GaN HEMT器件电特性退化的主要原因,同时也说明钝化可以有效地抑制60Co γ辐射感生表面态电荷,它是一种有效的加固手段。     

间歇供氨高温AlN缓冲层对AlGaN/GaN异质结的影响

研究了以间歇供氨的方法直接高温生长的氮化铝为缓冲层的AlGaN/GaN材料,高温氮化铝的应用可以有效的提高晶体质量和表面形貌,并且二维电子气的浓度和迁移率也得到改善。     

Effect of a high temperature AlN buffer layer grown by initially alternating supply of ammonia on AIGaN/GaN heterostuctures

The effect of a high temperature AlN buffer layer grown by the initially alternating supply of ammonia （IASA） method on AlGaN/GaN heterostructures was studied. The use of AlN by the IASA method can effectively increase the crystalline quality and surface morphology of GaN. The mobility and concentration of 2DEG of AlGaN/GaN heterostuctures was also ameliorated.     

X 波段氮化镓合成固态放大器

Based on a self-developed A1GaN/GaN HEMT with 2.5 mm gate width technology on a SiC substrate, an X-band GaN combined solid-state power amplifier module is fabricated. The module consists of an AIGaN/GaN HEMT, Wilkinson power couplers, DC-bias circuit and microstrip line. For each amplifier, we use a bipolar DC power source. Special RC networks at the input and output and a resistor between the DC power source and the gate of the transistor at the input are used for cancellation of self-oscillation and crosstalk of low-frequency of each amplifier. At the same time, branches of length 3λ/4 for Wilkinson power couplers are designed for the elimination of self-oscillation of the two amplifiers. Microstrip stub lines are used for input matching and output matching. Under Vds = 27 V, Vgs = -4.0 V, CW operating conditions at 8 GHz, the amplifier module exhibits a line gain of 5.6 dB with power added efficiency of 23.4%, and output power of 41.46 dBm （14 W）, and the power gain compression is 3 dB. Between 8 and 8.5 GHz, the variation of output power is less than 1.5 dB.