Fabrication of enhancement-mode high electron mobility transistors on AlGaN/GaN heterostructures grown on sapphire substrates is reported. These devices with 1.2μm gate-length,4mm space between source and drain,and 1...Fabrication of enhancement-mode high electron mobility transistors on AlGaN/GaN heterostructures grown on sapphire substrates is reported. These devices with 1.2μm gate-length,4mm space between source and drain,and 15nm recessed-gate depth exhibit a maximum drain current of 332mA/mm at 3V, a maximum transconductance of 221mS/mm, a threshold voltage of 0.57V, ft of 5.2GHz, and fmax of 9.3GHz. A dielectric layer formed unintentionally during recessedgate etching is confirmed by contrasting the Schottky I-V characteristics of pre-etching and post-etching. The frequency characteristics and subthreshold characteristics of the devices are studied in detail.展开更多
The mechanical and electric characteristics of a cantilever beam micro opto mechanical switch are studied theoretically,with which the dependence of the flexion on the applied voltage is derived,as well as the form...The mechanical and electric characteristics of a cantilever beam micro opto mechanical switch are studied theoretically,with which the dependence of the flexion on the applied voltage is derived,as well as the formula of the threshold voltage.The applied voltage,having no connection with the width of the beam,is in inverse proportion to the square of the beam's length.The deflection at the beam's tip cannot exceed 1/3 of the distance between two adjacent electrodes.These results are the basis of the switch design and development.展开更多
A novel MOS-only voltage reference is presented,which is based on the threshold voltage difference between p-type and n-type MOSFETs. Its precision is improved by the cancellation of the process variation. The referen...A novel MOS-only voltage reference is presented,which is based on the threshold voltage difference between p-type and n-type MOSFETs. Its precision is improved by the cancellation of the process variation. The reference has been successfully implemented in a Chartered 0.35μm CMOS process. The occupied chip area is 0. 022mm^2. Measurements indicate that without trimming, the average output voltage error is 6mV at room temperature compared with the simulation result. The temperature coefficient is 180ppm/℃ in the worst case in the temperature range of 0 to 100℃ ,and the line regulation is ± 1.1%. The reference is applied in an adaptive power MOSFET driver.展开更多
In order to suppress drain-induced barrier lowering in dual material gate SOI MOSFETs,halo doping is used in the channel near the source. Two-dimensional analytical models of surface potential and threshold voltage fo...In order to suppress drain-induced barrier lowering in dual material gate SOI MOSFETs,halo doping is used in the channel near the source. Two-dimensional analytical models of surface potential and threshold voltage for the novel SOI MOSFET are developed based on the explicit solution of the two-dimensional Poisson＇s equation. Its characteristic improvement is investigated. It is concluded that the novel structure exhibits better suppression of drain-induced barrier lowering and higher carrier transport efficiency than conventional dual material gate SOI MOSFETs. Its drain-induced barrier lowering decreases with increasing halo doping concentration but does not change monotonically with halo length. The analytical models agree well with the two-dimensional device simulator MEDICI.展开更多
基金the Key Programof the National Natural Science Foundation of China(No.60736033)~~
文摘Fabrication of enhancement-mode high electron mobility transistors on AlGaN/GaN heterostructures grown on sapphire substrates is reported. These devices with 1.2μm gate-length,4mm space between source and drain,and 15nm recessed-gate depth exhibit a maximum drain current of 332mA/mm at 3V, a maximum transconductance of 221mS/mm, a threshold voltage of 0.57V, ft of 5.2GHz, and fmax of 9.3GHz. A dielectric layer formed unintentionally during recessedgate etching is confirmed by contrasting the Schottky I-V characteristics of pre-etching and post-etching. The frequency characteristics and subthreshold characteristics of the devices are studied in detail.
文摘The mechanical and electric characteristics of a cantilever beam micro opto mechanical switch are studied theoretically,with which the dependence of the flexion on the applied voltage is derived,as well as the formula of the threshold voltage.The applied voltage,having no connection with the width of the beam,is in inverse proportion to the square of the beam's length.The deflection at the beam's tip cannot exceed 1/3 of the distance between two adjacent electrodes.These results are the basis of the switch design and development.
文摘A novel MOS-only voltage reference is presented,which is based on the threshold voltage difference between p-type and n-type MOSFETs. Its precision is improved by the cancellation of the process variation. The reference has been successfully implemented in a Chartered 0.35μm CMOS process. The occupied chip area is 0. 022mm^2. Measurements indicate that without trimming, the average output voltage error is 6mV at room temperature compared with the simulation result. The temperature coefficient is 180ppm/℃ in the worst case in the temperature range of 0 to 100℃ ,and the line regulation is ± 1.1%. The reference is applied in an adaptive power MOSFET driver.
文摘In order to suppress drain-induced barrier lowering in dual material gate SOI MOSFETs,halo doping is used in the channel near the source. Two-dimensional analytical models of surface potential and threshold voltage for the novel SOI MOSFET are developed based on the explicit solution of the two-dimensional Poisson＇s equation. Its characteristic improvement is investigated. It is concluded that the novel structure exhibits better suppression of drain-induced barrier lowering and higher carrier transport efficiency than conventional dual material gate SOI MOSFETs. Its drain-induced barrier lowering decreases with increasing halo doping concentration but does not change monotonically with halo length. The analytical models agree well with the two-dimensional device simulator MEDICI.
