Ryan M. Diestelhorst

Multiple-Bit Upset in 130 nm CMOS Technology

The probability of proton-induced multiple-bit upset (MBU) has increased in highly-scaled technologies because device dimensions are small relative to particle event track size. Both proton-induced single event upset (SEU) and MBU responses have been shown to vary with angle and energy for certain technologies. This work analyzes SEU and MBU in a 130 nm CMOS SRAM in which the single-event response shows a strong dependence on the angle of proton incidence. Current proton testing methods do not account for device orientation relative to the proton beam and, subsequently, error rate prediction assumes no angular dependencies. Proton-induced MBU is expected to increase as integrated circuits continue to scale into the deep sub-micron regime. Consequently, the application of current testing methods will lead to an incorrect prediction of error rates

An Investigation of Dose Rate and Source Dependent Effects in 200 GHz SiGe HBTs

We present an investigation of the observed variations in the total dose tolerance of the emitter-base spacer and shallow trench isolation oxides in a commercial 200 GHz SiGe HBT technology. Proton, gamma, and X-ray irradiations at varying dose rates are found to produce drastically different degradation signatures at the various oxide interfaces. Extraction and analysis of the radiation-induced excess base current, as well as low-frequency noise, are used to probe the underlying physical mechanisms. Two-dimensional calibrated device simulations are employed to correlate the observed results to the spatial distributions of carrier recombination in forward- and inverse-mode operation for both pre- and post-irradiation levels. Possible explanations of our observations are offered and the implications for hardness assurance testing are discussed

The Effects of Irradiation Temperature on the Proton Response of SiGe HBTs

We compare, for the first time, the effects of 63 MeV protons on 1st generation and 3rd generation SiGe HBTs irradiated at both liquid nitrogen temperature (77 K) and at room temperature (300 K). The 1st generation SiGe HBTs irradiated at 77 K show less degradation than when irradiated at 300 K. Conversely, the 3rd generation SiGe HBTs exhibits an opposite trend, and the devices irradiated at 77 K show enhanced degradation compared to those irradiated at 300 K. The emitter-base spacer regions for these two SiGe technologies are fundamentally different in construction, and apparently are responsible for the observed differences in temperature-dependent radiation response. At practical circuit biases, both SiGe technology generations show only minimal degradation for both at 77 K and 300 K exposure, to Mrad dose levels, and are thus potentially useful for electronics applications requiring simultaneous cryogenic temperature operation and significant total dose radiation exposure

Substrate Engineering Concepts to Mitigate Charge Collection in Deep Trench Isolation Technologies

Delayed charge collection from ionizing events outside the deep trench can increase the SEU cross section in deep trench isolation technologies. Microbeam test data and device simulations demonstrate how this adverse effect can be mitigated through substrate engineering techniques. The addition of a heavily doped p-type charge-blocking buried layer in the substrate can reduce the delayed charge collection from events that occur outside the deep trench isolation by almost an order of magnitude, implying an approximately comparable reduction in the SEU cross section

Laser-Induced Current Transients in Silicon-Germanium HBTs

Device-level current transients are induced by injecting carriers using two-photon absorption from a subbandgap pulsed laser and recorded using wideband transmission and measurement equipment. These transients exhibit three distinct temporal trends that depend on laser pulse energy as well as the transverse and vertical charge generation location. The nature of the current transient is controlled by both the behavior of the subcollector-substrate junction and isolation biasing. However, substrate potential modulation, due to deformation of the subcollector-substrate depletion region, is the dominant mechanism affecting transient characteristics.

An 8–16 GHz SiGe Low Noise Amplifier With Performance Tuning Capability for Mitigation of Radiation-Induced Performance Loss

We present a wideband, low noise amplifier (LNA) implemented in a Silicon-Germanium Heterojunction Bipolar Transistor (SiGe HBT) technology. This SiGe LNA covers a frequency range of 8-16 GHz and achieves a peak gain of 17.5 dB at nominal bias and a peak OIP3 of 15.8 dBm at 10 GHz at nominal bias. The noise figure (NF) of the LNA is 4.5-8.1 dB across band, and it nominally consumes 4 mA from a 4 V supply. Samples were irradiated with 63.3 MeV protons to proton-equivalent doses ranging from 200 krad(Si) to 2 Mrad(Si). This LNA incorporates bias control “tuning-knobs” to enable bias tuning to mitigate for RF performance loss due to total dose exposure and process variation in performance metrics. The effectiveness of the tuning “knobs” to compensate for lost post-irradiated performance was investigated. It was found that the LNA performance can be restored with the use of the tuning knobs with a performance tuning algorithm.

Single Event Upset Mechanisms for Low-Energy-Deposition Events in SiGe HBTs

Microbeam measurements and TCAD simulations are used to examine the effects of ion angle of incidence on the charge collected from events occurring in a Silicon Germanium (SiGe) Heterojunction Bipolar Transistor (HBT). The results identify the geometrically driven charge-collection mechanisms that dominate the low LET broad beam SEU response. The deep trench isolation that surrounds the transistor significantly modulates the charge transport and, therefore, the charge collected by the collector. A new way of estimating critical charge, , for upset in SiGe HBT circuits is proposed based on TCAD simulation results and measured broadbeam data.

The Application of RHBD to n-MOSFETs Intended for Use in Cryogenic-Temperature Radiation Environments

Proton and X-ray irradiation effects are investigated in 0.35 m conventional, annular, and ringed-source radiation-hardening-by-design (RHBD) CMOS devices. Transistors were irradiated with protons at both 300 K and 77 K. Radiation-induced oxide trapped charges in the shallow trench isolation (STI) oxide deplete the p-substrate and effectively shunt the source and drain, inducing off-state leakage. Without the STI, RHBD nFETs exhibit no radiation-induced off-state shunt leakage currents for devices irradiated at both 300 K and 77 K. Conventional 0.35 mum pFETs were not degraded by proton irradiation, since the leakage path cannot be formed in the n-well. A simple CMOS logic inverter shows no degradation in output voltage after proton irradiation for all tested temperature and bias conditions. More advanced 130 nm node nFETs show less TID sensitivity to STI leakage due possibly to the smaller physical STI volume and/or additional doping located on the STI sidewall.

A 6–20 GHz Adaptive SiGe Image Reject Mixer for a Self-Healing Receiver

A wideband (6-20 GHz) Silicon-Germanium (SiGe) adaptive image-reject mixer with an intermediate frequency (IF) of 1.8 GHz is presented. The mixer can be “self-healed” to deliver consistent performance by nullifying the effects of process variations, environmental changes, or aging. Various performance metrics of the mixer can also be adapted to different specifications across multiple frequency bands. A conversion gain greater than 15 dB, an image rejection ratio (IRR) exceeding 35 dB, and an output 1-dB compression point greater than 10 dBm, were obtained in measurement. An automated self-healing procedure is developed and shown to be effective for improving the measured performance of the mixer. The mixer was fabricated in a 150 GHz peak fT, 200 nm SiGe BiCMOS process technology and consumes 215 mA of current operating off a 4 V rail.

The Effects of X-Ray and Proton Irradiation on a 200 GHz/90 GHz Complementary

We investigate the effects of both X-ray and proton irradiation on a novel 200 GHz/90 GHz (npn/pnp) complementary SiGe:C HBT technology. The DC forward mode total dose tolerance of the pnp HBTs is shown to exceed that of the npn HBTs by a significant margin after being subjected to both 63-MeV proton and 10-keV X-ray sources, while the AC characteristics of both devices exhibit no degradation up to X-ray doses as high as 1.8 Mrad(SiO2). Pre- and post-irradiation results from a current feedback operational amplifier implemented in this technology and irradiated up to a dose of 1.8 Mrad(SiO2) are presented, showing no degradation in performance metrics under two low current density bias configurations.