A model predicting the behavior of various parameters, such as 2DEG sheet charge density and thresh- old voltage, with the variation of barrier thickness and oxide thickness considering interface density of states is ...A model predicting the behavior of various parameters, such as 2DEG sheet charge density and thresh- old voltage, with the variation of barrier thickness and oxide thickness considering interface density of states is presented. The mathematical dependence of these parameters is derived in conjunction with the interface density of states. The dependence of sheet charge density with the barrier thickness and with the oxide thickness is plotted and an insight into the barrier scaling properties of AIInN based MOSHEMTs is presented. The threshold voltage is also plotted with respect to barrier thickness and oxide thickness, which reveals the possibility of the enhance- ment mode operation of the device at low values of the interface DOS. The results are in good agreement with the fabricated device available in the literature.展开更多
目的:探究正常肺组织、肺腺癌癌旁和肺腺癌中所有基因的表达水平趋势,寻找特征性基因并进行实验验证。方法:下载加州大学圣克鲁斯分校(University of California,Santa Cruz,UCSC)数据中心中癌症基因组图谱(the cancer genome atlas,TC...目的:探究正常肺组织、肺腺癌癌旁和肺腺癌中所有基因的表达水平趋势,寻找特征性基因并进行实验验证。方法:下载加州大学圣克鲁斯分校(University of California,Santa Cruz,UCSC)数据中心中癌症基因组图谱(the cancer genome atlas,TCGA)和基因型-组织表达项目(genotype-tissue expression,GTEX)的整合数据,采用R语言分析所有基因的表达趋势,寻找特征性基因,提取癌旁和肿瘤组织共同高表达的基因集,进行GO和KEGG分析富集情况,鉴定最显著的通路中在肺组织和癌旁及肺腺癌中变化最大的基因。通过细胞生物学实验验证候选基因在肿瘤中的作用。结果:整合数据显示存在一群正常组织中低表达但在肺腺癌癌旁和肺腺癌中高表达的基因(DEGS2、PIGY、FUCA、GM2A),GO分析显示该基因群富集最显著的通路是膜脂质代谢过程,对该通路基因和符合趋势的基因取交集,发现DEGS2在癌旁和癌组织中升高最明显,升高倍数达3.27倍。实验证实,敲除DEGS224 h后细胞迁移能力下降,72 h后细胞活性下降55.0%。结论:DEGS2在癌旁和肺腺癌中呈高表达,其表达能促进肺腺癌的增殖和迁移,从而进一步驱动从癌旁组织到癌的发展。展开更多
We have developed a physics based analytical model for the calculation of threshold voltage, two dimensional electron gas（2DEG） density and surface potential for Al Ga N/Ga N metal oxide semiconductor high electron ...We have developed a physics based analytical model for the calculation of threshold voltage, two dimensional electron gas（2DEG） density and surface potential for Al Ga N/Ga N metal oxide semiconductor high electron mobility transistors（MOSHEMT）. The developed model includes important parameters like polarization charge density at oxide/Al Ga N and Al Ga N/Ga N interfaces, interfacial defect oxide charges and donor charges at the surface of the Al Ga N barrier. The effects of two different gate oxides（Al_2O_3 and HfO_2/ are compared for the performance evaluation of the proposed MOSHEMT. The MOSHEMTs with Al_2O_3 dielectric have an advantage of significant increase in 2DEG up to 1.2 10^（13） cm^2 with an increase in oxide thickness up to 10 nm as compared to HfO_2 dielectric MOSHEMT. The surface potential for HfO_2 based device decreases from 2 to –1.6 e V within10 nm of oxide thickness whereas for the Al_2O_3 based device a sharp transition of surface potential occurs from 2.8to –8.3 e V. The variation in oxide thickness and gate metal work function of the proposed MOSHEMT shifts the threshold voltage from negative to positive realizing the enhanced mode operation. Further to validate the model,the device is simulated in Silvaco Technology Computer Aided Design（TCAD） showing good agreement with the proposed model results. The accuracy of the developed calculations of the proposed model can be used to develop a complete physics based 2DEG sheet charge density and threshold voltage model for Ga N MOSHEMT devices for performance analysis.展开更多
We present a two-dimensional electron gas （2DEG） charge-control mobility variation based drain cur- rent model for sheet carrier density in the channel. The model was developed for the AIInGaN/A1N/GaN high- electron...We present a two-dimensional electron gas （2DEG） charge-control mobility variation based drain cur- rent model for sheet carrier density in the channel. The model was developed for the AIInGaN/A1N/GaN high- electron-mobility transistor. The sheet carrier density model used here accounts for the independence between the Fermi levels Ef and ns along with mobility for various AI and In molefractions. This physics based ns model fully depends upon the variation of El, u0, the first subband E0, the second subband El, and as. We present a physics based analytical drain current model using ns with the minimum set of parameters. The analytical resuks obtained are compared with the experimental results for four samples with various molefraction and barrier thickness. A good agreement between the results is obtained, thus validating the model.展开更多
文摘A model predicting the behavior of various parameters, such as 2DEG sheet charge density and thresh- old voltage, with the variation of barrier thickness and oxide thickness considering interface density of states is presented. The mathematical dependence of these parameters is derived in conjunction with the interface density of states. The dependence of sheet charge density with the barrier thickness and with the oxide thickness is plotted and an insight into the barrier scaling properties of AIInN based MOSHEMTs is presented. The threshold voltage is also plotted with respect to barrier thickness and oxide thickness, which reveals the possibility of the enhance- ment mode operation of the device at low values of the interface DOS. The results are in good agreement with the fabricated device available in the literature.
文摘目的:探究正常肺组织、肺腺癌癌旁和肺腺癌中所有基因的表达水平趋势,寻找特征性基因并进行实验验证。方法:下载加州大学圣克鲁斯分校(University of California,Santa Cruz,UCSC)数据中心中癌症基因组图谱(the cancer genome atlas,TCGA)和基因型-组织表达项目(genotype-tissue expression,GTEX)的整合数据,采用R语言分析所有基因的表达趋势,寻找特征性基因,提取癌旁和肿瘤组织共同高表达的基因集,进行GO和KEGG分析富集情况,鉴定最显著的通路中在肺组织和癌旁及肺腺癌中变化最大的基因。通过细胞生物学实验验证候选基因在肿瘤中的作用。结果:整合数据显示存在一群正常组织中低表达但在肺腺癌癌旁和肺腺癌中高表达的基因(DEGS2、PIGY、FUCA、GM2A),GO分析显示该基因群富集最显著的通路是膜脂质代谢过程,对该通路基因和符合趋势的基因取交集,发现DEGS2在癌旁和癌组织中升高最明显,升高倍数达3.27倍。实验证实,敲除DEGS224 h后细胞迁移能力下降,72 h后细胞活性下降55.0%。结论:DEGS2在癌旁和肺腺癌中呈高表达,其表达能促进肺腺癌的增殖和迁移,从而进一步驱动从癌旁组织到癌的发展。
文摘We have developed a physics based analytical model for the calculation of threshold voltage, two dimensional electron gas（2DEG） density and surface potential for Al Ga N/Ga N metal oxide semiconductor high electron mobility transistors（MOSHEMT）. The developed model includes important parameters like polarization charge density at oxide/Al Ga N and Al Ga N/Ga N interfaces, interfacial defect oxide charges and donor charges at the surface of the Al Ga N barrier. The effects of two different gate oxides（Al_2O_3 and HfO_2/ are compared for the performance evaluation of the proposed MOSHEMT. The MOSHEMTs with Al_2O_3 dielectric have an advantage of significant increase in 2DEG up to 1.2 10^（13） cm^2 with an increase in oxide thickness up to 10 nm as compared to HfO_2 dielectric MOSHEMT. The surface potential for HfO_2 based device decreases from 2 to –1.6 e V within10 nm of oxide thickness whereas for the Al_2O_3 based device a sharp transition of surface potential occurs from 2.8to –8.3 e V. The variation in oxide thickness and gate metal work function of the proposed MOSHEMT shifts the threshold voltage from negative to positive realizing the enhanced mode operation. Further to validate the model,the device is simulated in Silvaco Technology Computer Aided Design（TCAD） showing good agreement with the proposed model results. The accuracy of the developed calculations of the proposed model can be used to develop a complete physics based 2DEG sheet charge density and threshold voltage model for Ga N MOSHEMT devices for performance analysis.
文摘We present a two-dimensional electron gas （2DEG） charge-control mobility variation based drain cur- rent model for sheet carrier density in the channel. The model was developed for the AIInGaN/A1N/GaN high- electron-mobility transistor. The sheet carrier density model used here accounts for the independence between the Fermi levels Ef and ns along with mobility for various AI and In molefractions. This physics based ns model fully depends upon the variation of El, u0, the first subband E0, the second subband El, and as. We present a physics based analytical drain current model using ns with the minimum set of parameters. The analytical resuks obtained are compared with the experimental results for four samples with various molefraction and barrier thickness. A good agreement between the results is obtained, thus validating the model.
