共查询到18条相似文献,搜索用时 171 毫秒
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利用半导体PN结偏置过程的理论模型,类比分析了玻璃的热及电场极化过程。理论分析表明,在热及电场极化条件下,正、负电极与玻璃分界面处的电场及电荷分布规律与其在反向、正向偏置的2个PN结处非常相似;利用PN结偏置模型,并考虑玻璃极化过程中电子的作用,修正了极化玻璃中电场分布和载流子运动方程及其边界条件,并解释了一些已有实验现象。 相似文献
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熔融石英的热及电场诱导机理 总被引:1,自引:0,他引:1
详细分析了熔融石英样品经热及电场诱导后 ,建立二阶极化率的机理。该机理表明 ,二阶极化率是由样品耗尽区中偶极子的定向和三阶极化率经强静电场作用共同形成的。在一般条件下诱导 ,前者是主要因素 ;在较高电压诱导时 ,后者是主要因素。推导了二阶极化率的表达式 ,并进行了数值计算。数值结果表明 ,在一般情况下 ,χ3 3 ( 2 ) 约 1pm/V ,χ3 3 ( 2 ) ∶χ3 1( 2 ) 约为 3。理论证明提高诱导的外加电压和选用Na和OH杂质浓度较大的石英材料能提高二阶极化率。 相似文献
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GeS2-Ga2S3-CdS硫系玻璃的电致二阶非线性光学效应 总被引:9,自引:2,他引:9
采用熔融-急冷法制备了在可见光区有较高透射率的GeS2-Ga2S3-CdS硫系玻璃,通过麦克尔(Maker)条纹法观察电场-温度场极化的片状样品中的二阶非线性光学效应,并讨论了该效应的机理。结果表明,在270℃极化30 min,当极化电压大于2 kV/mm时,观察到明显的二阶非线性光学效应,且二次谐波强度的大小随极化电压的增大而增大。二次谐波效应的产生是玻璃中的偶极子在电场作用下的取向调整,破坏了玻璃的宏观各向同性所致,二次谐波强度出现最大值的入射角与偶极子的取向调整程度有关。 相似文献
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本文采用热极化技术在掺锗玻璃条形光波导中诱导出非线性光学效应,并通过变化光波导结构改变极化内电场的大小,研究热极化条件对诱导出的电光效应的影响。研究发现在最佳极化时间内,加入薄SiON层的光波导结构经极化后电光效应积累快,相同极化条件下诱导出的电光系数比原有的条形光波导增大约22%,同时极化光波导还存在一个较低的极化阈值电压。实验结果表明加入光波导结构中的薄SiON层可在一定程度上改变极化光波导内的电荷分布,实现强化其内部电场增大光波导内的非线性光学效应或电光效应的目的。 相似文献
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横向超结功率器件遭受衬底辅助耗尽效应,这破坏了超结的电荷平衡,降低了器件的耐压。本文研究了一种基于增强介质层电场的解决方法,以提高横向超结器件(SJ-LDMOS)的耐压。通过高密度的界面电荷增强埋氧层(BOX)的电场从而提高埋氧层的耐压,这可以削弱纵向电场对超结的影响,消除衬底辅助耗尽效应,促进超结电荷平衡。为了获得理想的线性电场增强效果,一种具有槽形埋氧层的超结器件(TBOX SJ-LDMOS)被提出。槽形埋氧层能根据纵向电场的大小自适应地收集空穴,在埋氧层表面形成近似线性的电荷分布,这促进了超结的电荷平衡,提高了SJ-LDMOS器件的耐压,并使其接近理想超结的耐压值。 相似文献
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Depletion layer properties have been calculated for an exponential-constant p-n junction in silicon by using a simple model. Closed-form expressions are presented for the built-in voltage V/sub bi/ and the offset voltage correction Delta V, respectively, for this junction. These formulas allow the depletion capacitance to be accurately determined from a given value of applied voltage V/sub a/ by manual calculations. The results obtained can readily be extended to other semiconductor materials and other diffused p-n junctions.<> 相似文献
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Hagino H. Yamashita J. Uenishi A. Haruguchi H. 《Electron Devices, IEEE Transactions on》1996,43(3):490-500
Thermal and electrical destructions of n-ch 600 V punchthrough type IGBTs in F.B.SOA are investigated by experiments and simulations, The cause of the thermal destruction is the thermal disappearance of built-in potential of p-n junction between the n+ emitter and the p base of the IGBT integral DMOSFET occurring at the critical temperature of ~650 K. Experiment and simulation results for the critical temperature show a good agreement. The cause of the electrical destruction is impact ionization at the n- drift/n+ buffer junction in addition to the n- drift/p base junctions. That triggers a positive feedback mechanism of increasing IGBT integral pnp transistor current which causes the device to lose gate controllability. The experimentally obtained critical power dissipation is ~2000 kW/cm2. This value is ten times greater than BJTs. It was also found that emitter ballast resistance (EBR) plays an important role in describing the F.B.SOA of IGBTs 相似文献
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计算了放射源在半导体中沿厚度方向的能量沉积,并以此计算β辐射伏特效应电池的理想短路电流。通过对比实测短路电流和理想短路电流可以得到β辐射伏特效应电池PN结内建电场的扩散长度。在上述基础上,本文给出了β辐射伏特效应电池内建电场厚度设计原则: 放射源在半导体中能量沉积厚度和PN结内建电场中载流子的扩散长度两者中较小的应作为β伏特效应电池内建电场厚度设计值,如果沉积厚度远远大于载流子扩散长度,则说明多结结构较适合该类β伏特效应电池果,多结的结数应约为沉积厚度与载流子扩散长度的比。 相似文献
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《Electron Devices, IEEE Transactions on》1983,30(8):954-957
Extremely high breakdown voltages with very low leakage current have been achieved in plane and planar p-n junctions by using an ion-implemented junction extension for precise control of the depletion region charge in the junction termination. A theory is presented which shows a greatly improved control of both the peak surface and bulk electric fields in reverse biased p-n junctions. Experimental results show breakdown voltages greater than 95 percent of the ideal breakdown voltage with lower leakage currents than corresponding unimplanted devices. As an example, diodes with a normal breakdown voltage of 1050 V and a 0.5 mA leakage current become 1400 V (1450 ideal) devices with a 5 µA leakage current. Applications of the junction termination technique is feasible in MOS technology, but is more attractive in power devices where reduced surface fields are as important as the extremely high breakdown voltages. Reduced surface fields allow more flexibility in passivation techniques, two of which we have used to date. Our results also show that the implant can be activated at a variety of temperatures with a good degree of success; process flexibility being the goal of these tests. 相似文献
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A new contribution to reverse-biased junction capacitance is reported. This component arises from trench isolation stress-induced bandgap narrowing that changes the built-in potential. Experimental junction capacitance measurements show good correlation to simulated oxidation stresses. The reported data agrees well with the predicted values from basic device equations. Stress induced capacitance increase of 12% (7.5%) at 3.3 V reverse bias for p+/n (n+/ p) junctions, respectively is observed. In addition, well-understood reverse junction leakage relation to stress is also reported. This phenomenon will become increasingly important as trenches become shallower and more tightly spaced 相似文献
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Surface breakdown in silicon planar junctions is analysed with emphasis on the evaluation of the critical field (i.e., the maximum electric field within the depletion region at breakdown). This parameter is determined by a computer-aided experimental procedure consisting in relaxation field calculations with boundary conditions governed by junction breakdown voltage (at given gate voltage) as measured on specially processed gate-controlled diodes. The idealization (infinite doping) of the highly doped side of the junction, encountered in previous works, has been eliminated. Values of the critical field determined are in the range of 1 × 106 V/cm (1·0 × 106 V/cm for 1·0 μm gate-oxide and 1·4 × 106 V/cm for 0·3 μm gate-oxide). These values are substantially higher than those estimated by other authors (5–6 × 105 V/cm) and are consistent with independent experimental findings on avalanche (hot-carrier) injection in silicon diodes. 相似文献
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