200-mm CVD Grown Si/SiGe Resonant Interband Tunnel Diodes Optimized for High Peak-to-Valley Current Ratios

Negative differential resistance (NDR) devices in conjunction with MOS transistors will provide a high speed, low power alternate to complementary metal oxide semiconductor (CMOS) technology [1]. Boolean logic with gate-level pipelining has been demonstrated using monostable-bistable logic (MOBILE) gates [1]. Application to low-power embedded memory is also promising [2]. A key hurdle for tunneling based devices is development of a manufacturable process that can be integrated into a CMOS process line. Monolithic integration of low-temperature molecular beam epitaxy (LT-MBE) grown Si/SiGe resonant interband tunnel diodes (RITD) with NMOS [3] has been demonstrated. However, chemical vapor deposition (CVD) is the dominant epitaxial growth technique for semiconductor manufacturing. The first CVD grown Si/SiGe RITD was demonstrated with a peak-to-valley current ratio (PVCR) of 1.85 [4]. In this work, further optimization of boron δ-doping has resulted in high PVCR up to 5.2. Current density dependence on tunneling barrier thickness is also investigated.