The Resonant tunneling diode (RTD) is a high speed nanoelectronic device based on quantum resonant tunneling effect. It has the advantage of high frequency, low operating Voltage, low power dissipation, negative resistance, bistability and self-latching. It can be applied in high speed integrated circuits widely.
Based on the analysis of correlation between the device characteristic parameters and the material structure parameters, some design rules have been summarized as following:
1. The barrier width LB of RTD should be selected as narrow as possible to increase the peak current density Jp.
2. The well width LW should be selected slightly wider to decrease the peak Voltage Vp.
3. The spacer width LS should be selected slightly narrower to decrease the peak Voltage Vp.
4. The emitter doping density NE should be determined to a reasonable value to avoid both RS and intrinsic capacitance Cd too much.
5. Selecting AlAs as the barrier material to increase the barrier height then to increase peak valley current ratio (PVCR).
6. In emitter region, adding a narrow bandgap material layer to form a subwell. The 3dimension/2dimension resonant tunneling changes to 2dimension/3dimension resonant tunneling, the PVCR will be improved.
From above design rules, The GaAs based MBE material structure of RTD has been designed, The RTD devices have been fabricated from this material structure shown very good performance. Main characteristic parameters listed as following: Room temperature PVCR 7.6, fR=54GHZ, switching time tr≈171ps.