Leland Stanford Junior University

Inphi Corporation

Japan Science and Technology Corporation

Nptest, Inc.

Francis Ho

David M Bloom

Alfred S Hou

Yoshihisa Yamamoto

Kenneth R Wilsher

There is disclosed a memory system and method. The memory system may include a plurality of memory planes including two or more data memory areas, and a memory controller adapted to controlling reading, writing, and erasing of the plurality of memory planes. When any one of the data memory areas is occupied with one of a write operation and an erase operation, the controller may reconstruct data stored in the one occupied data memory area by reading parity information and data stored in the plurality of memory areas other than the one occupied data memory area.

High throughput flash memory system

A method of probing voltage comprises: establishing electrical connectivity between a conductor to be probed and a first terminal of a photoconductive switch; during a sampling interval n, applying a laser pulse to the photoconductive switch while applying a voltage to a second terminal of the photoconductive switch corresponding to a voltage sample taken during a prior sampling interval n&minus;1, such that current flow through the photoconductive switch is dependent on any difference between voltage of the conductor and the applied voltage; converting the current flow to a voltage signal; passing the voltage signal during a gating interval and sampling the passed voltage signal to produce a voltage sample for the sampling interval n. A repetitive test pattern applied to the conductor and the sampling interval is synchronized with the repetitive test pattern. Converting the current flow to a voltage signal can comprise applying the current flow to a current-to-voltage converter having a rise time which is less than the gating interval. The voltage signal can be passed only during the gating interval so that the voltage sample is insensitive to any leakage through the photoconductive switch outside of the gating interval. Passing the voltage signal during a gating interval can comprise applying the voltage signal to a first transistor Q of a differential pair of transistors Q Q applying a reference voltage to a second transistor Q of the differential pair of transistors, and controlling common emitter current of the differential pair of transistors with an electronic switch so as to pass the voltage signal when the electronic switch is closed. Sampling the voltage signal can comprises applying the voltage signal to an analog-to-digital converter and enabling the analog-to-digital converter to prepare a digital sample of the voltage signal representing voltage on the conductor. Apparatus for carrying out the method is also provided.

Photoconductive-sampling voltage measurement

A method of making released structures by using at least two directional etching steps. Cantilevers, bridges and many other structures can be made with the present invention. In a preferred embodiment, two directional etching steps are performed at opposing angles nonnormal to the substrate surface such that the substrate is undercut and a structure is released. Alternatively, more than two directional etching steps may be performed at various angles. For example, the substrate may be rotated continuously during the directional etching process. A cantilever formed by the method of the present invention necessarily has a substantially triangular cross section. Directional etching processes that can be used include focused ion beam etching and ECR plasma etching. Some directional etching processes may require the use of a patterned etch resist layer. Other etching processes such as focused ion beam etching may use scanning techniques to select which regions are etched. A backside etch can be performed to remove remaining substrate material under the released micromachined structure. The method is particularly well suited for making released cantilevers.

Method of making released micromachined structures by directional etching

An all-electrical high frequency contact sampling probe provides sub-micron spatial resolution and picosecond or sub-picosecond temporal resolution. In a preferred embodiment, the probe is a monolithic integration of a sampling circuit with a cantilever and probe tip, where the distance between the circuit and the tip is less than a wavelength of interest in an RF signal �V.sub.RF !. The sampling circuit �44! uses Schottky diodes �SD! for sampling the RF signal �V.sub.RF ! from a device under test at a rate determined by local oscillator signals �50, 52!. An IF signal �V.sub.IF ! produced by the sampling probe is an equivalent time representation of the RF signal. Applications include testing signals at interior nodes of high speed integrated circuits.

Electrical contact probe for sampling high frequency electrical signals

A potentiometry apparatus for measuring a periodic electrical waveform existing proximate the surface of a sample such as a semiconductor wafer is disclosed herein. The potentiometry apparatus includes a pulse generator for generating a sequence of electrical pulses at a pulse frequency offset from the frequency of the surface waveform by a mixing frequency. A cantilever coupled to the pulse generator serves to carry the electrical pulses to a position proximate the surface of the sample. In a capacitive displacement mode the cantilever is mechanically displaced so as to generate a time-expanded representation of the electrical surface waveform having a repetition frequency equal to the mixing frequency. During displacement mode operation an optical detection circuit may be employed to monitor deflection of the cantilever. In a tunneling current mode the cantilever is again employed to carry the electrical pulses to a position proximate the surface of the sample. In this mode a tunneling current propagating through the cantilever at the mixing frequency provides a time,expanded representation of the electrical surface waveform.

System and method for high-speed potentiometry using scanning probe

A potentiometry apparatus for measuring a periodic electrical waveform existing proximate the surface of a sample such as a semiconductor wafer is disclosed herein. The potentiometry apparatus includes a pulse generator for generating a sequence of electrical pulses at a pulse frequency offset from the frequency of the surface waveform by a mixing frequency. A cantilever coupled to the pulse generator serves to carry the electrical pulses to a position proximate the surface of the sample. In a capacitive displacement mode the cantilever is mechanically displaced so as to generate a time-expanded representation of the electrical surface waveform having a repetition frequency equal to the mixing frequency. During displacement mode operation an optical detection circuit may be employed to monitor deflection of the cantilever. In a tunneling current mode the cantilever is again employed to carry the electrical pulses to a position proximate the surface of the sample. In this mode a tunneling current propagating through the cantilever at the mixing frequency provides a time-expanded representation of the electrical surface waveform.

Growing community of inventors

Palo Alto, CA, United States of America

Francis Ho