注FCC4007电路的电子和X射线辐照效应

分析研究了用注Ｆ工艺制作的ＣＣ４００７ 电路电子和Ｘ射线辐照响应结果。实验表明,把适量的Ｆ注入栅场介质,能明显抑制辐射所引起的ＰＭＯＳＦＥＴ 阈电压的负向漂移和ＮＭＯＳＦＥＴ阈电压的正向回漂及静态漏电流的增加。Ｉ－Ｖ特性表明,栅介质中的Ｆ能减小辐射感生氧化物电荷和界面态的增长积累。注Ｆ栅介质电子和Ｘ射线辐照敏感性的降低,是Ｓｉ－Ｆ结键释放了Ｓｉ／ＳｉＯ２ 界面应力,并部分替换在辐照场中易成为电荷陷阱的Ｓｉ－Ｈ弱键的缘故。     

电离辐射引起MOSFET跨导退化的机制

通过研究６０Ｃｏｒ射线对ＭＯＳＦＥＴ跨导的影响，定性描述了辐照栅偏置条件以及氧化物电荷积累和Ｓｉ／ＳｉＯ２界面态密度增加分别与ＮＭＯＳＦＥＴ和ＰＭＯＳＦＥＴ跨导衰降之间的依赖关系。试验表明，对于ＰＭＯＳＦＥＴ，电离辐射感生氧化物正电荷累和界面太度增加降导致器件跨导退化。对于ＮＭＯＳＦＥＴ来说。这种退化只与辐射感生界面态密度增长有关。     

注F CC4007电路的电离辐射效应

本文分析研究了用注Ｆ工艺制作的ＣＣ４００７电路Ｃｏ６０γ辐照响应结果．实验表明、把适量的Ｆ引入栅介质，能明显减少辐射感生氧化物电荷积累和界面态的增长，从而引起较小的阈电压漂移和Ｎ沟静态漏电流的增长．器件导电类型和辐照栅偏压不改变注Ｆ栅介质的抗辐照特性．注Ｆ栅介质辐照敏感性的降低可归结为Ｆ能减小Ｓｉ／ＳｉＯ２界面应力、并部分替换在辐照场中易成为电荷陷阱的应力键和弱健等的缘故．     

多晶硅栅光刻前后注F对MOS器件辐照特性的影响

分析研究了Ｈ２＋Ｏ２合成栅氧化、多晶硅栅光刻前后注Ｆ和Ｐ的沟和Ｎ沟ＮＯＳＦＥＴ，在最劣γ辐照偏置下的阈电压和Ｉ（ｄｓ）－Ｖ（ｇｓ）亚阈特性的辐射影响应．结果表明，多晶硅栅光刻前注Ｆ比光刻后注Ｆ和未注Ｆ，具有更强的抑制辐射感生氧化物电荷积累和界面态生长的能力．其辐射敏感性的降低可能归结为ＳｉＯ２栅介质和Ｓｉ／ＳｉＯ２界面附近Ｆ的浓度相对较大以及栅场介质中Ｆ注入缺陷相对较少所致．     

多晶硅栅光刻前后注F对MOS器件辐射特性的影响

分析研究了Ｈ２＋Ｏ２合成栅氧化、多晶硅栅光刻前后注Ｆ和Ｐ的沟和Ｎ沟ＮＯＳＦＥＴ，在最劣γ辐照偏置下的阈电压和Ｉｄｓ－Ｖｇｓ亚阈特性的辐射影响应。结果表明，多晶硅栅光刻前注Ｆ比光刻后注Ｆ和未注Ｆ，具有更强的抑制辐射感生氧化物电荷积累和界面态生长的能力。其辐射敏感性的降低可能归结为ＳｉＯ２栅介质和Ｓｉ／ＳｉＯ２界面附近Ｆ的浓度相对较大以及栅场介质中Ｆ注入缺陷相对较少所致。     

MOSFET电离辐射感生跨导退化的简单模型

本文提出了一个能有效反映辐射感生氧化物电荷积累和Ｓｉ／ＳｉＯ２界面态密度增加分别对ＭＯＳＦＥＴ跨导退化影响的简单模型．通过模型与实验结果比较，讨论了不同沟道类型ＭＯＳＦＥＴ（ＮＭＯＳＦＥＴ和ＰＭＯＳＦＥＴ）跨导退化的机制．     

两种注F能量的栅介质电离辐射响应特性

对栅氧化后３０ｋｅＶ与４３ｋｅＶＦ离子注入的Ｐ沟ＭＯＳＦＥＴ进行了电离辐射响应特性的比较．结果发现，３０ｋｅＶ注Ｆ具有较强的抑制辐射感生氧化物电荷和界面态增长的能力．用３０ｋｅＶ注Ｆ具有较少注入缺陷的模型对实验结果进行了讨论．     

NMOS低温热载流子晶体管的解析研究

利用低温（７７－２９５Ｋ）短沟ＮＭＯＳＦＥＴ准二维解析模型，研究了７７－２９５Ｋ温区ＮＭＯＳＦＥＴ衬底电流相关的物理机制。发现沟道电子平均自由程不随温度而改变，其值约为７．６ｎｍ；低温下虽然沟道电子在漏端获得较高的能量，但由于碰撞电离减弱，使ＮＭＯＳＦＥＴ的衬底电流不随温度降低而显著增长。实验结果证明，提出的衬底电流机制和模型适用于７７－２９５Ｋ宽温区范围。     

高压偏移栅P沟MOSFET的电离辐照性能研究

详细研究了高压偏移栅Ｐ沟ＭＯＳＦＥＴ在Ｃｏ＾６０－γ辐照下击穿电压随辐照剂量的变化关系。结果表明：；击穿电压的辐照剂量响应与漂移区杂质面密度、票移区长度、场板长度以及漏区结构有关。另外，γ辐照志致导通电阻增加。结果证实了我们以前提出的电离辐照引起击穿电压变化的机制。对实验现象给出了比较圆满的解释。结论对研制电离辐射加固高压偏移栅Ｐ沟ＭＯＳＦＥＴ具有重要的指导作用。     

CMOS／SIMOX和CMOS／BESOI的γ射线辐照特性比较

用薄膜ＳＩＭＯＸ（ＳｅｐａｒａｔｉｏｎｂｙＩＭｐｌａｎｔａｔｉｏｎｏｆＯＸｙｇｅｎ）、厚膜ＢＥＳＯＩ（ｆｆｅｎｄｉｎｇａｎｄＥｔｃｈ－ｂａｃｋＳｉｌｉｃｏｎＯｎＩｎｓｕｌａｔｏｒ）和体硅材料制备了ＣＭＯＳ倒相器电路，并用６０Ｃｏγ射线进行了总剂量辐照试验。在不同偏置条件下，经不同剂量辐照后，分别测量了ＰＭＯＳ、ＮＭＯＳ的亚阈特性曲线，分析了引起ＭＯＳＦＥＴ阈值电压漂移的两种因素（辐照诱生氧化层电荷和新生界面态电荷）。对ＮＭＯＳ／ＳＩＭＯＸ，由于寄生背沟ＭＯＳ结构的影响，经辐照后背沟漏电很快增大，经３００Ｇｙ（Ｓｉ）辐照后器件已失效。而厚膜ＢＥＳＯＩ器件由于顶层硅膜较厚，基本上没有背沟效应，其辐照特性优于体硅器件。最后讨论了提高薄膜ＳＩＭＯＸ器件抗辐照性能的几种措施。     

GaN HEMT器件中子辐照效应实验研究

建立了GaN HEMT器件(氮化镓高电子迁移率晶体管)中子原位测试技术和辐照效应实验方法,开展了GaN HEMT器件脉冲反应堆中子辐照效应实验研究,重点研究了电离辐射和位移损伤对器件性能退化的影响,获取了GaN HEMT中子位移损伤效应敏感参数和效应规律.结果表明,阈值电压、栅极泄漏电流以及漏极电流是中子辐照损伤的敏感...     

Does short wavelength lithography process degrade the integrity of thin gate oxide?

This paper presents the results of investigation on integrity of X-ray/E-beam irradiated thin gate oxides. A large increase of gate oxide leakage current is observed after irradiation on thin gate oxide under X-ray/E-beam lithography conditions. This radiation-induced leakage current (RILL) can be removed by a thermal annealing at 400°C and above, without adverse effect to the oxide integrity. In addition, it is found that ionizing exposures do not significantly affect the breakdown and quasi-breakdown characteristics in ultra-thin oxide.     

Total dose dependence of radiation-induced leakage current in ultra-thin gate oxides

Radiation-induced leakage current (RILC) has been studied on ultra-thin gate oxides (4 and 6 nm) irradiated with 8 MeV electrons. Both RILC and stress-induced leakage current (SILC) have been fitted with the same Fowler–Nordheim law, suggesting that RILC and SILC have similar conduction mechanisms. The RILC dependence from total dose during irradiation has been analysed and compared with the SILC dependence from the cumulative injected charge. Different growth laws of RILC and SILC have been found in the two cases. The intensity of positive and negative RILC also depends on the applied gate bias voltage during irradiation, probably reflecting different distributions of the oxide traps mediating the trap assisted tunnelling. Finally, we have presented the first evidence of a quasi-breakdown phenomenon due to ionizing radiation.     

总剂量辐照对65 nm NMOSFET热载流子敏感参数的影响

为了研究总剂量辐射对纳米MOS晶体管热载流子效应的影响,对65 nm 体硅工艺的NMOS器件进行了总剂量辐射和热载流子试验,对比了辐射前后不同宽长比器件的跨导、栅极泄漏电流、线性饱和电流等电参数。结果表明,MOS器件的沟道宽度越窄,热载流子效应受辐射的影响越显著,总剂量辐射后热载流子效应对器件的损伤增强。分析认为,辐射在STI中引入的陷阱电荷是导致以上现象的主要原因。该研究结果为辐射环境下器件的可靠性评估提供了依据。     

Al_2O_3栅介质的制备工艺及其泄漏电流输运机制

利用室温下反应磁控溅射结合炉退火的方法在P Si(10 0 )衬底上制备了Al2 O3 栅介质层,研究了不同的溅射气氛和退火条件对Al2 O3 栅介质层物理特性的影响.结果表明:在较高温度下N2 气氛中退火有助于减小泄漏电流;在O2 气氛中退火有助于减少Al2 O3 栅介质中的氧空位缺陷.对Al2 O3 栅介质泄漏电流输运机制的分析表明,在电子由衬底注入的情况下,泄漏电流主要由Schottky发射机制引起,而在电子由栅注入的情况下,泄漏电流可能由Schot tky发射和Frenkel Poole发射两种机制共同引起.     

The leakage current improvement in an ultrashallow junction NMOSwith Co silicided source and drain

The leakage current characteristics of the cobalt silicided NMOS transistors with a junction depth of 800 Å have been studied. In order to minimize the junction leakage current, the thickness of the CoSi₂ layer should he controlled under 300 Å and the Si surface damage induced by the gate spacer etch should be minimized. The post furnace annealing after the second silicidation by the rapid thermal annealing (RTA) process also affected the leakage current characteristics. The gate induced drain leakage (GIDL) current was not affected by the lateral encroachment of CoSi₂ layer into the channel direction when the gate spacer length was larger than 400 Å     

Electron irradiation of field-controlled thyristors

The influence of 3-MeV electron irradiation upon the characteristics of asymmetrical field-controlled thyristors has been examined for fluences of up to 16 Mrad. In addition to the lifetime reduction due to the radiation damage, carrier removal effects have also been observed in the very lightly doped n-base region of these devices. The leakage current, even after radiation at the highest fluenee, is not significantly increased and the blocking characteristies of these devices are not degraded. In fact, a small improvement in the blocking gain has been observed at low gate voltages. The electron irradiation has been found to increase the forward voltage drop during current conduction and to reduce the forced gate turn-off time. Gate turn-off times of less than 500 ns have been achieved by irradiation with a fluence of 16 Mrad. However, this is accompanied by a large increase in the forward voltage drop. Tradeoff curves between the forward voltage drop and the gate turn-off time have been obtained. From these curves, it has been determined that gate turnoff times of 1 µs can be obtained without a significant increase in the forward voltage drop for devices capable of blocking up to 600 V.     

Stability of submicron AlGaN/GaN HEMT devices irradiated by gamma rays

AlGaN/GaN high electron mobility transistors (HEMTs) with 0.75 μm gate-length and incorporated C-doped GaN buffer layers have been exposed to gamma radiation. The devices have been irradiated to cumulative doses up to 10⁷ rad. The effect of gamma irradiation on the direct current (DC) and low-frequency noise properties of these devices have been investigated in reference to the unexposed device. The DC and noise characteristics show deteriorating device performance upon the gamma exposure. However, some DC parameters, such as transconductance, tended to recover after the irradiation. The gate leakage current and low-frequency noise power spectra indicate this trend even couple of months after the irradiation.     

Effects of gamma irradiation on the insulated-gate bipolar transistor

The effects of gamma irradiation on the International Rectifier IRGBC20 insulated-gate bipolar transistor (IGBT) was investigated. These devices were found to be sensitive to gamma irradiation due to their metal-oxide-semiconductor field-effect-transistor (MOSFET) input drive. Total doses as small as 50 Krads(Si) increased the saturated collector current (I_c) by an order of magnitude when the irradiation was performed with zero gate bias. For a constant (V_g − V_th) of 0.5 V, I_c decreased to about half its pre-irradiation value after irradiation to 40 Krads(Si). The threshold voltage of the MOSFET shifted in the negative direction with the largest and smallest shifts occurring for a positive and negative gate bias applied during the irradiation, respectively. The shift in threshold voltage saturated at the cut-in voltage of the P-i-N diode portion of the device, indicating that gamma irradiation does not affect the P-i-N diode. The reverse blocking leakage current of the device is not very sensitive to radiation below a total dose of 400 Krads(Si), but increases sharply for larger doses. All of these radiation-degraded characteristics of the IGBT are primarily the result of increasing interface-state and oxide-trapped charge densities with total radiation dose, which decreases the carrier channel mobility by increased carrier scattering. Both room temperature and 150°C annealing were observed to partially recover all of the device characteristics by reducing the radiation-induced oxide-trapped charges.     

Gate Bias Effect on the 60-MeV Proton Irradiation Response of 65-nm CMOS nMOSFETs

The response to a 60-MeV proton irradiation of nMOSFETs fabricated in a 65-nm CMOS technology using a 1.4-nm gate oxide is reported. A strong dependence on the gate bias during the exposure is found. Whereas no degradation is observed for 0-V bias, soft or hard breakdown occurs under normal operational conditions, i.e., 1.2 V on the gate. Furthermore, it is noted that the breakdown happens preferentially at the source–gate junctions. Possible mechanisms are discussed, whereby at the moment, it is believed that a synergy between the radiation damage in the thin gate oxide and the gate current flow under constant voltage may explain the observations. Furthermore, it is shown that the tendency for a breakdown at the source–gate junction is correlated with a higher source–gate current prior to irradiation. This could point to some processing-induced prerad local degradation of the gate oxide, which develops into a breakdown leakage site under biased 60-MeV proton irradiation.